What is a soft bounce?

A soft bounce in email marketing happens when an email can't be delivered to a recipient's inbox, but the problem is only temporary. Think of it like trying to mail a letter to a house where the mailbox is overflowing, or the post office is temporarily closed. The mail isn't rejected forever; it just can't get through right at that moment.Unlike a hard bounce, which means an email address is permanently invalid, a soft bounce suggests there's a chance the email could be delivered successfully later. Email service providers (ESPs) usually try to resend soft-bounced emails a few times over a short period. If the email still can't be delivered after these attempts, it might eventually turn into a hard bounce or be removed from your list by your ESP.Understanding soft bounces is important for anyone sending emails, whether it's for newsletters, promotions, or transactional messages. It helps you keep your email list clean and ensures your messages reach your audience effectively, protecting your sender reputation.

Why soft bounces matter

Soft bounces are more than just a minor inconvenience; they can impact your email marketing efforts in several ways. First, every soft bounce means a message didn't reach its intended recipient, which translates to missed opportunities for engagement, sales, or information sharing. If you're sending a promotional offer, a soft bounce means that potential customer didn't see it.Second, a high number of soft bounces can signal to internet service providers (ISPs) and email service providers (ESPs) that your sending practices might be problematic. While not as severe as hard bounces, a consistently high soft bounce rate could negatively affect your sender reputation over time. A poor sender reputation can lead to more of your emails being sent to spam folders or even blocked entirely, even for recipients whose inboxes are working perfectly. This is why monitoring and understanding your bounce rates, both soft and hard, is crucial for maintaining good email deliverability. It helps ensure your valuable messages land where they belong: in the inbox.

Common reasons for soft bounces

Several factors can cause an email to soft bounce. Knowing these reasons can help you troubleshoot and improve your email deliverability.

Recipient's mailbox is full

This is one of the most common reasons. The recipient simply has too many emails in their inbox and hasn't cleared it out. There's no space for new messages.

Server is down or offline

The recipient's email server might be temporarily unavailable, undergoing maintenance, or experiencing technical issues. This prevents new emails from being received until the server is back up.

Mailbox is not configured correctly

Sometimes, the recipient's email account might have temporary settings issues, like an auto-reply loop or an unusual forwarding setup that causes bounces.

Email size is too large

If your email, especially with large attachments or very heavy images, exceeds the recipient's server's size limit, it can be soft bounced. This is less common with modern email platforms but can still happen.

Temporary network issues

Brief internet connectivity problems or routing issues between your email server and the recipient's server can cause a temporary failure to deliver.

How to reduce soft bounce rates

Reducing soft bounce rates involves a combination of good email list management and optimized sending practices.

Regularly clean your email list

While soft bounces are temporary, repeatedly bouncing emails can indicate a recipient is inactive or has long-term issues. Periodically review your list for addresses that consistently soft bounce and consider removing them if they never become deliverable. Many email marketing platforms will automatically manage this for you, converting repeated soft bounces into hard bounces or unsubscribing the contact.

Segment your audience

Sending highly relevant content to engaged segments of your audience can encourage better inbox management. People are less likely to let an inbox fill up if they're eagerly awaiting your content.

Optimize email size

Be mindful of the overall size of your emails. Compress images and avoid embedding excessively large files. While most modern email clients handle larger files, keeping emails lean can help prevent size-related bounces.

Monitor your sending reputation

Use tools provided by your email service provider to track your bounce rates, open rates, and click-through rates. A sudden spike in soft bounces could indicate a broader issue with your sender reputation that needs addressing, such as being flagged by an ISP.

Warm up new IP addresses

If you're sending from a new IP address, gradually increase your sending volume. This "warming up" process helps establish a good sender reputation with ISPs and prevents them from seeing a sudden large volume of mail as suspicious.Soft bounces are a normal part of email marketing, but understanding their causes and taking steps to manage them is key to maintaining a healthy email list and strong sender reputation. By monitoring your bounce rates, keeping your list clean, and optimizing your email content, you can ensure your messages have the best chance of reaching your audience.