Emails sent to default JIRA inbox are bounced back

Summary

When sending an email to the default JIRA inbox, jira@instancename.atlassian.net, the emails are being bounced back with a failed delivery message.

Environment

JIRA Cloud

Steps to Reproduce

1. Send an email to jira@instancename.atlassian.net

Expected Results

Email is received by JIRA, and issue or comment is created.

Actual Results

No ticket/comment is created and an email is received with the following failed delivery message.

'This message could not be delivered.
Action: failed
Final-Recipient: rfc822; jira@instancename.atlassian.net
Original-Recipient: rfc822; jira@instancename.atlassian.net
Diagnostic-Code: smtp; 550 5.1.1 Mailbox does not exist
Status: 5.1.1'

Workaround

Atlassian support has a manual workaround to re-enable the mailbox. Please raise a ticket with support to have this resolved.