When creating an SMTP Server in Confluence, you may find that upon submission you are presented with a HTTP 400 error, stating that "The request sent by the client was syntactically incorrect".

The cause for this problem is unknown at this time. We've seen this problem affecting Google Chrome Version 40.0.2214.95 (64-bit), but we have not been able to reproduce it.

Workaround

Use an alternative web browser such as Mozilla Firefox to create the Mail Server.

If you run into this problem, please get in touch with Atlassian Support - we'd be very keen in determine the root cause of this issue.