What is a Soft Bounce in Email Marketing?

Understanding Email Bounces: The Basics

Before we zoom in on soft bounces, let’s quickly cover the fundamentals.

What is an Email Bounce?

Simply put, an email bounce occurs when an email message cannot be delivered to the recipient’s email address. The recipient’s mail server sends a notification back to the sender’s server—often called a Non-Delivery Report (NDR) or bounce message—explaining why it couldn’t deliver the email. Mail Transfer Agents (MTAs), which handle email routing, process these messages.

Two Main Types of Email Bounces

Email bounces generally fall into two main categories:

1. Hard Bounces: These signify a permanent delivery failure. The email address is invalid, non-existent, or the receiving server has permanently blocked delivery.
2. Soft Bounces: These indicate a temporary delivery failure. The email address is valid, but an issue currently prevents the email from being delivered.

This article will focus on the nuances of soft bounces.

Deep Dive into Soft Bounces

Understanding soft bounces is crucial because, while temporary, they can still affect your email marketing performance if you don’t address them.

Defining a Soft Bounce

A soft bounce occurs when the recipient’s server returns an email to the sender because a temporary issue prevented its delivery to the recipient’s inbox. The key here is “temporary.” Unlike hard bounces, a soft bounce doesn’t necessarily mean the email address is bad or that you can never email that person again. In many cases, the email might be deliverable if resent at a later time.

Common Causes of Soft Bounces

Several situations can lead to a soft bounce. Here are some of the most frequent culprits:

Mailbox Full

This is a classic reason for a soft bounce. The recipient’s inbox has reached its storage capacity and cannot accept new messages.

• How it happens: The user hasn’t deleted old emails, or their email provider offers limited storage.
• Why it’s temporary: If the recipient clears space in their mailbox, subsequent emails may be delivered successfully.

Server Temporarily Unavailable/Offline

The recipient’s email server might be experiencing temporary difficulties.

• How it happens: The server could be down for scheduled maintenance, experiencing an unexpected outage, overloaded with traffic, or facing other technical glitches.
• Why it’s temporary: Once the server issues resolve, it should accept emails again.

Email Message Size Too Large

Your email, including text, images, and any attachments, might exceed the size limit set by the recipient’s email server.

• How it happens: High-resolution images or large file attachments can significantly increase email size. Different servers have different size restrictions.
• Why it’s temporary: If you resend a smaller version of the email, or if the recipient’s server limits change, the email might go through.

Auto-Reply/Out of Office

Automated responses, like “out of office” notifications, aren’t always classified as “bounces” by every system. However, email service providers (ESPs) sometimes report them similarly to soft bounces. These auto-replies can also contribute to a “mailbox full” scenario if the recipient is away for a long time.

• How it differs: This isn’t a delivery failure per se, but an automated acknowledgment of receipt with additional context (e.g., the person is away). However, if a mailbox continuously sends auto-replies and becomes full, new emails will then soft bounce.

Greylisting

This is a spam-fighting technique some email servers use. When a server receives an email from an unknown sender (or an unfamiliar IP address/sending server combination), it temporarily rejects the email with a “try again later” message.

• How it works: Legitimate mail servers will attempt to resend the email after a short interval. Spammers often don’t bother. If the sending server retries, the receiving server typically accepts the email and may whitelist the sender for future messages.
• Why it’s temporary: It’s designed as a one-time (or infrequent) check for new senders.

DNS Issues

Temporary problems with the Domain Name System (DNS) records for the recipient’s domain can prevent your server from finding the recipient’s mail server.

• How this can disrupt delivery: DNS translates human-readable domain names (like example.com) into IP addresses that computers use. If these records are temporarily incorrect or unavailable, mail cannot route properly.

Throttling by ESP/ISP

The recipient’s Email Service Provider (ESP) or Internet Service Provider (ISP) might be throttling email delivery. This means they intentionally limit the number of emails they will accept from your sending IP address or domain within a certain timeframe.

• Why this is a temporary measure: Providers often do this to prevent spam or manage server load. If you’re sending large volumes, your ESP might need to “warm up” your IP, or you might be sending too quickly for the recipient server’s preference.

Other Temporary Technical Issues

Sometimes, less common technical glitches on either the sending or receiving end can cause a temporary delivery hiccup.

Differentiating Soft Bounces from Hard Bounces

It’s vital to distinguish between these two bounce types as they require different actions.

Feature	Soft Bounce	Hard Bounce
Nature	Temporary delivery issue	Permanent delivery failure
Common Reasons	Mailbox full, server temporarily down, email size limit exceeded, greylisting	Invalid email address, domain doesn’t exist, recipient server blocked sender
Sender Action	Monitor; ESP usually retries automatically. Persistent issues may need review.	Remove email address from the list immediately.
Retry by ESP?	Yes, typically retried for a limited period.	No, ESP usually suppresses the address automatically.
Impact (Short-term)	Minor, if isolated. Affects immediate campaign reach for that contact.	Delivery failure to that contact.
Impact (Long-term)	Can harm sender reputation if frequent or unresolved; may become a hard bounce.	Significantly damages sender reputation if not removed; wastes resources.

To sum up, soft bounces are temporary email delivery failures. They indicate that the recipient’s email address is likely valid, but a transient problem currently prevents your message from reaching their inbox. Most email marketing platforms will attempt to redeliver these messages automatically.

The Impact of Soft Bounces on Your Email Marketing Efforts

You might think, “If they’re temporary, why worry too much?” However, ignoring soft bounces can lead to several problems down the line.

Why You Can’t Ignore Soft Bounces

Even though they represent temporary setbacks, persistent soft bounces can be a red flag. They can:

• Indicate underlying issues with your list or sending practices.
• Eventually harm your sender reputation.

Impact on Deliverability Metrics

Soft bounces directly influence your overall bounce rate. While a high hard bounce rate clearly signals list quality problems, a rising soft bounce rate also warrants attention. Differentiating between the two in your analytics helps you understand the true nature of your delivery challenges.

Sender Reputation Damage

Internet Service Providers (ISPs) and Email Service Providers (ESPs) monitor sender behavior closely. A consistently high soft bounce rate can make your sending domain or IP address look unreliable. If recipient servers frequently encounter temporary issues delivering your mail (even if it’s their server’s fault sometimes), they might start to view your mail with more suspicion. This can lead to:

• An increased likelihood of your emails landing in the spam folder.
• Your emails being throttled more aggressively.
• In severe cases, your emails being blocked altogether.

Your sender reputation is a valuable asset; work diligently to protect it!

Wasted Resources

Sending emails that don’t get delivered, even temporarily, consumes resources. For high-volume senders, this can translate to:

• Increased costs if your email platform charges per email sent.
• Inefficient use of your sending infrastructure.
• A skewed understanding of your campaign’s return on investment (ROI).

Inaccurate Campaign Performance Data

If a portion of your emails soft bounce, your key performance indicators (KPIs) like open rates and click-through rates will be based on a smaller actual delivered number than your total sent number. This makes it harder to:

• Assess true subscriber engagement.
• Make informed decisions about your email content and strategy.

Potential Escalation to Hard Bounces

Many ESPs have policies where if an email address consistently soft bounces over a certain period or for a specific number of consecutive campaigns (e.g., “mailbox full” for three campaigns in a row), they will eventually reclassify that soft bounce as a hard bounce. The ESP will then suppress the address to protect your sender reputation.

In short, while not as immediately critical as hard bounces, soft bounces can negatively affect your deliverability, tarnish your sender reputation, waste resources, and distort your campaign analytics if not properly managed.

How Email Service Providers (ESPs) Handle Soft Bounces

Modern ESPs, including robust toolkits designed for WordPress like Send by Elementor, have built-in mechanisms to manage soft bounces intelligently.

Automatic Retry Mechanisms

One of the defining characteristics of how ESPs handle soft bounces is through automatic retries. When an email soft bounces, the ESP typically won’t just give up. Instead, it will attempt to resend the email at later intervals.

• Typical retry schedules: These vary by ESP, but a common pattern might be to retry after 15 minutes, then an hour, then a few hours, then once a day, for up to a few days (e.g., 72 hours). The goal is to deliver the message once the temporary issue resolves without overwhelming the receiving server.

Soft Bounce Thresholds and Escalation

ESPs also track how often soft bounces occur for individual email addresses.

• Tracking repeated soft bounces: They log how many times an email to a specific address soft bounces and often the reasons.
• Conversion to hard bounce/suppression: If an address soft bounces for the same reason (e.g., mailbox full) across multiple consecutive campaigns, or if it soft bounces too many times within the retry window for a single campaign, the ESP will often treat it as a hard bounce. This means the ESP will add the address to a suppression list to prevent further sending attempts to it, which ultimately protects your sender reputation.
• Understanding ESP policies: It’s important for web creators to be aware of how their chosen email platform handles these scenarios. This information is usually available in the provider’s documentation.

Reporting and Analytics

A good ESP provides clear reports on all aspects of email delivery, including detailed bounce information.

• Campaign reports: You should be able to see the number of soft bounces for each campaign.
• Deliverability dashboards: Some platforms offer dashboards that give an overview of your bounce trends.
• Using these reports: By monitoring these analytics, you can identify patterns. For instance, are soft bounces higher for a particular campaign? Is one specific bounce reason (like “message size too large”) appearing frequently? Send by Elementor, for example, emphasizes clear, real-time analytics. This is invaluable for diagnosing such issues directly within the WordPress dashboard.

Best Practices for Managing and Reducing Soft Bounces

Proactive management can significantly minimize the occurrence and impact of soft bounces. This is particularly relevant for web creators managing email marketing for their clients, often within a WordPress and WooCommerce environment.

Monitor Your Bounce Reports Regularly

Don’t just send and forget. Make a habit of checking your campaign reports.

• Identify High Soft Bounce Rates: What’s “high”? While there’s no universal number, a soft bounce rate consistently exceeding 2-3% for multiple campaigns warrants investigation. Pay attention to sudden spikes.
• Segment by Bounce Reason: If your ESP provides this level of detail (many do), look at why emails are soft bouncing. A high number of “mailbox full” bounces might suggest list fatigue or unengaged subscribers. Frequent “message too large” bounces point to an issue with your email content.

Maintain Good List Hygiene (Even for Soft Bounces)

While list hygiene is paramount for hard bounces, it also plays a role with soft bounces.

• Encourage Subscribers to Whitelist Your Address: Ask new subscribers to add your “from” email address to their contact list or safe sender list. This can help prevent your emails from being mistakenly flagged by spam filters or subjected to aggressive greylisting.
• Manage Inactive Subscribers: Regularly review subscribers who haven’t engaged with your emails for a long time (e.g., 6+ months). While their addresses might still be valid, their mailboxes could be unattended and therefore prone to becoming full. Consider sending a re-engagement campaign, and if there’s no response, you might decide to remove them.

Optimize Email Content

The content of your email itself can sometimes cause a soft bounce.

• Keep Email File Sizes Manageable:
  • Compress images: Use tools to optimize images for the web before embedding them.
  • Avoid large attachments: If you need to share a large file, upload it to a cloud storage service and include a download link in your email instead of attaching the file directly.
  • Recommended sizes: Aim to keep your total email size (HTML, text, and images) under 100-200KB if possible, though many recipient servers accept larger sizes up to a few megabytes. Check your ESP’s recommendations.
• Avoid Spam Triggers: While spam filters more directly link to emails going to the junk folder rather than bouncing, overly aggressive filtering on the recipient’s server could sometimes manifest as a temporary rejection (especially if combined with other factors like sender reputation).
  • Be mindful of using excessive capitalization, too many exclamation points, misleading subject lines, and spammy keywords. Ensure your HTML is clean and not overly complex.

Check Your Sending Infrastructure (If Applicable)

For those managing their own sending servers or using basic WordPress mail functions, this is critical.

• Ensure Proper Authentication (SPF, DKIM, DMARC):
  • SPF (Sender Policy Framework): An email authentication method that specifies which mail servers are authorized to send email for your domain.
  • DKIM (DomainKeys Identified Mail): Adds a digital signature to your emails. This allows receiving servers to verify that you actually sent the message and that it hasn’t been tampered with.
  • DMARC (Domain-based Message Authentication, Reporting & Conformance): An email authentication policy and reporting protocol. It builds on SPF and DKIM, telling receiving servers what to do with emails that fail authentication (e.g., reject them or send them to spam).
  • These authentication methods are crucial for building trust with recipient servers. They can significantly reduce issues like greylisting or emails being flagged as suspicious, which can sometimes lead to temporary rejections.
  • Using a dedicated email marketing toolkit that integrates smoothly with WordPress, like Send by Elementor, often helps ensure correct configuration or simplifies these technical aspects. Such platforms are built to handle these complexities, making it easier for web creators.

Understand Recipient Server Behavior

Occasionally, you might notice that a particular domain (e.g., @somecompany.com) has a higher rate of soft bounces for your campaigns. This could indicate that their mail server has stricter policies, lower mailbox quotas, or is more prone to temporary outages. While you can’t control their server, being aware of this can help in your analysis.

What to Do About Repeated Soft Bounces to the Same Address

• Consider Manual Review (for high-value contacts): If a very important contact consistently soft bounces with “mailbox full,” and your ESP hasn’t yet suppressed them, you might consider reaching out through an alternative channel if appropriate (e.g., LinkedIn, a phone call) to let them know. Use this tactic sparingly and judiciously.
• Respect ESP Policies: Trust your ESP’s automated processes. They design these to protect your sender reputation. If your ESP suppresses an address after repeated soft bounces, don’t try to manually re-add it to your active list unless you confirm the issue is resolved. Continuing to send to problematic addresses will harm your deliverability to everyone else.

Leveraging WordPress and WooCommerce for Better Deliverability

For web creators, the WordPress environment is home. Using tools designed for it makes a difference.

• Ensure Your WordPress Sending Method is Robust: The default wp_mail() function in WordPress uses PHP mail. This method is often unreliable for bulk email marketing and can lead to deliverability problems. It’s highly recommended to use a professional SMTP service or an email sending platform that uses robust API-based sending. Tools like Send by Elementor are built specifically for WordPress and WooCommerce, implying they utilize more reliable sending mechanisms than the default.
• Keep WordPress and Plugins Updated: Outdated software can have security vulnerabilities or compatibility issues that might indirectly affect your site’s ability to send email correctly or maintain a good reputation. Regular updates are part of good digital hygiene.

To effectively manage soft bounces: regularly monitor bounce reports, maintain list hygiene, optimize email content (especially size), ensure proper sender authentication, and understand your ESP’s bounce handling policies. For WordPress users, choosing sending solutions designed for the platform significantly simplifies these tasks.

When a Soft Bounce Becomes a Hard Bounce

As mentioned, soft bounces aren’t always temporary in practice.

The Transition Point

Most ESPs have a threshold for how many times they will retry a soft-bounced email or over what period. If an email address:

• Soft bounces for the same reason (e.g., “mailbox full,” “server unavailable”) across several consecutive campaigns.
• Or, soft bounces a certain number of times (e.g., 5-10 retries) for a single campaign without successful delivery. …the ESP will typically reclassify that soft bounce as a hard bounce. The exact number of attempts or duration varies by provider.

Implications of This Reclassification

Once an ESP reclassifies an address as a hard bounce due to persistent soft bouncing:

• The ESP will add that address to your suppression list.
• The ESP will not send further emails to that address from your account.
• Your ESP will count it as a hard bounce in your analytics.

Why This is a Necessary Process

This reclassification is a protective measure. Continuously attempting to send emails to addresses that are consistently unable to receive them (even for “temporary” reasons that prove to be persistent) signals to ISPs that you are not managing your list well. This damages your sender reputation. Suppressing these addresses helps maintain your deliverability to the rest of your list.

Send by Elementor and Soft Bounce Management

For web creators using WordPress, an integrated solution can make managing email deliverability, including soft bounces, far more straightforward.

Built for WordPress: A Smoother Experience

A toolkit like Send by Elementor, designed as a WordPress-native solution, aims to provide this seamless experience.

• Simplified Management: By operating within the familiar WordPress dashboard, web creators can manage their email marketing without constantly switching platforms.
• Reduced Conflicts: This native integration can help avoid common plugin conflicts or data syncing issues that sometimes affect external marketing platforms when working with WordPress data. Such a stable environment contributes to more reliable email sending.

Clear Analytics and Reporting

Understanding bounce data is key. Send by Elementor emphasizes providing clear, real-time analytics.

• Informed Decisions: This allows web creators and their clients to easily see bounce reports, including soft bounce details, directly within WordPress. This visibility empowers them to diagnose issues and take corrective actions promptly.
• Demonstrating Value: Clear reporting also helps creators demonstrate the effectiveness and challenges of email campaigns to their clients.

Automated Handling (Intelligent by Design)

While specific retry logic is proprietary to each ESP, systems like Send by Elementor are generally designed to handle bounces according to industry best practices.

• Automated Retries & Suppression: This typically includes automatic retries for soft bounces and eventual suppression of addresses that consistently fail to deliver. This process protects the user’s sender reputation with minimal manual work. This “set-and-forget” aspect for routine bounce management frees up creators to focus on strategy.

Focusing on What Matters: Client Growth

Ultimately, the goal of any marketing tool is to help businesses grow. By efficiently handling the technical complexities of email deliverability, including soft bounce management, solutions like Send by Elementor empower web creators to:

• Offer more comprehensive services to their clients.
• Focus on creating high-impact email campaigns that drive engagement, customer retention, and revenue, rather than getting bogged down in delivery minutiae.

Conclusion

Soft bounces are a common, yet often misunderstood, aspect of email marketing. While they signify temporary delivery issues, you should not dismiss them. Monitoring your soft bounce rates, understanding their causes, and implementing best practices for email content and list management are crucial for maintaining a strong sender reputation and ensuring your messages reach your audience.

For web creators, particularly those working within the WordPress and WooCommerce ecosystem, leveraging tools that simplify and automate aspects of deliverability management can be a game-changer. By understanding how soft bounces work and how your email platform handles them, you can optimize your email strategies, provide better value to your clients, and ultimately contribute to their growth and success.

Frequently Asked Questions (FAQ) about Soft Bounces

Here are some common questions web creators and marketers have about soft bounces:

How many times will an email soft bounce before it’s considered a hard bounce?

This varies significantly between Email Service Providers (ESPs). Some might retry for 24-72 hours, making several attempts. If delivery still fails after this period or after a set number of consecutive campaign failures to that address (for example, 3-5 times for “mailbox full”), the ESP will often reclassify it as a hard bounce and suppress the address. Check your specific ESP’s documentation for their policy.

Can I manually resend an email that soft bounced?

Most ESPs automate the retry process for soft bounces. Manual resending is usually unnecessary and not recommended for individual soft bounces. If an address consistently soft bounces, investigate the cause rather than just resending. Continuously trying to send to an address that your ESP wants to suppress can harm your sender reputation.

Does a soft bounce mean the recipient’s email address is bad?

Not necessarily. A soft bounce indicates a temporary problem. The email address itself is usually valid. However, factors like a full mailbox, a temporary server outage on the recipient’s end, or an overly large email message currently prevent delivery. If a “temporary” issue persists indefinitely (like a mailbox that’s never cleared), it effectively becomes a permanent problem.

Will fixing soft bounces improve my open rates?

Indirectly, yes. If you reduce soft bounces, more of your emails will be successfully delivered to inboxes. This means more recipients will have the opportunity to open your emails. Furthermore, managing soft bounces helps protect your overall sender reputation. This makes it more likely that your emails will land in the inbox rather than the spam folder, which also positively influences open rates.

What’s an acceptable soft bounce rate?

There isn’t one magic number, as it can depend on your industry, list age, and sending frequency. However, most experts suggest that a soft bounce rate consistently below 2-3% is generally considered healthy. More important than a single number is monitoring the trend. If your soft bounce rate suddenly spikes for a campaign or starts to creep up over time, it’s a signal to investigate. Focus on the reasons for the soft bounces to address underlying issues.