Jira does not bounce back emails that are not processed by incoming mail handlers which uses Default mail server

Issue Summary

When Jira does not process an incoming email it does not bounce the email back!

Steps to Reproduce

1. Configure the incoming mail handler to create/add a comment to issue
   • Do not set a default reporter.
   • Set create user to False

1. Send an email to the mail handler's email address from a user(not in the cloud instance) with an issue-key in the subject

Expected Results

The email should be bounced back, possibly with an appropriate error/failure message!

Actual Results

The incoming email is not processed and silently ignored(not bounced back)

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available