A soft bounce occurs when an email is temporarily rejected by the recipient mail server. Unlike a hard bounce, which indicates a permanent failure, a soft bounce signals a temporary issue that may resolve on its own. Member365 will continue attempting delivery for a limited period when a soft bounce occurs.
This article explains what causes soft bounces, how Member365 handles them, and the steps you can take to improve deliverability.
What Causes a Soft Bounce
Soft bounces occur for several temporary reasons. Common examples include:
Mailbox is full
The recipient inbox has reached its storage limit and cannot accept new messages until space is cleared.
Temporary server issues
The recipient mail server may be offline, overloaded, or experiencing performance delays at the time of delivery.
Email size restrictions
The message may exceed the size limits imposed by the recipient server.
Temporary filtering or security checks
Security systems may delay acceptance for scanning or throttling purposes, especially when many messages are sent to the same organisation.
Link or domain filtering
Some servers use reputation services like Invaluement. A message can soft bounce if it contains a link or domain that has been flagged. For example: 550 Blocked by ivmLinkingDomains
This means a link in the email has been identified by the Invaluement reputation service as suspicious and the server has temporarily rejected it.
How Soft Bounces Affect Deliverability
Soft bounces do not harm sender reputation the way hard bounces do. However, repeated soft bounces from the same contact or organisation can indicate a deeper delivery issue that may begin to affect inbox placement over time.
Member365 continues retrying delivery for soft bounces, but if an address continues to produce soft bounces, the system may temporarily pause attempts to avoid being flagged by recipient servers.
How to Troubleshoot Soft Bounces
If you notice a large number of soft bounces or if internal email addresses appear in your bounce list, the following actions will help resolve the issue.
Step one: Review the affected message
Check for any large attachments, oversized images, or links that may trigger filtering.
Step two: Check for flagged links
If the bounce reason references ivmLinkingDomains or a similar service, review the URLs used in the email. Remove or replace any domain that may be listed on a reputation service. The sender can look up the flagged domain using the link provided in the bounce message.
Step three: Ask your IT team to whitelist Member365
Many soft bounces occur when an organisation mail server does not yet recognise the Member365 sending domain. Your IT team should whitelist Member365 sending domains and IP addresses to ensure smooth delivery. This is especially important when multiple team members appear on the soft bounce list.
Step four: Confirm the recipient mailbox status
Ask the recipient to confirm that their mailbox is active, not full, and not blocking bulk communications.
Step five: Monitor for repeat issues
If the same addresses continue to soft bounce, share the bounce details with the Member365 support team. We can help you determine whether it is a content issue, a server setting, or a domain reputation concern.
Summary
Soft bounces are temporary delivery failures and often resolve once the underlying condition changes. While they do not carry the same long term consequences as hard bounces, they can still affect timely communication if not addressed.
By reviewing message content, confirming mailbox status, and ensuring Member365 is whitelisted by your IT team, most soft bounce issues can be resolved quickly.
If you require help interpreting a specific bounce message or would like assistance improving deliverability, please contact the Member365 support team.
Comments
Please sign in to leave a comment.