Email to Jira connector not working for one user. How to fix?

[Paul Smee]

I have one user who, when they send an email to Jira, the email is added to an existing issue as a comment instead of creating a new issue. No matter what subject or how different the email is to this particular issue it always has the same result.

The logs show the following items that are of interest:

IncomingMail[10100]: There are no default applications configured, new users are not assigned to any groups therefore they can not create issues.

IncomingMail[10100]: Sender is anonymous, no default reporter specified and creating users is set to false (or external user management is enabled). Message rejected.

java.io.IOException: Unable to create a temporary file to copy attachment into.

I've tried to follow the details in this link but it still happens (though i did not try giving a new email address as I shouldn't have the change the email address of this administrator just for Jira)

https://confluence.atlassian.com/jirakb/mail-handler-fails-to-create-issue-from-certain-email-addresses-in-jira-server-827097833.html