For whatever reason that a JIRA notification email bounces back to Atlassian Cloud's mail server, the recipient's email address will be blocked in the system. At this state, no further notification emails can be sent out to the blocked email address. Furthermore, there are no indications in JIRA cloud that an email address is in this state.
- Send out an email notification to an email address with a full mailbox.
- An error message should be indicated somewhere that the email bounced back and that the email address is blocked. There should be a threshold for bounces before adding the email address into the drop list.
- The email address will be blocked in the mail server and the JIRA users has no indication that the email address is in this current state.
Atlassian Support can trace these notification emails and unblock the email addresses but there are no indicators in JIRA that can warn users of the current state of the email address. The email address will remain in this state until they reach out to Atlassian support to troubleshoot missing notification emails.
Please contact Atlassian Support to check if the missing notification emails is related to this issue.