Adding .eml attachment does not work

Question

Adding an .eml or .zip attachment does not work.

Whenever I try to add it in a comment, I receive a warning:

We couldn't save your comment

It might be empty or have invalid formatting. If you copy-pasted, try removing the formatting and adding it directly in the editor.

Whenever I try to add it a a individual attachment, I get a warning:

We couldn't save your attachment

Reload the issue then try adding it again.

Does anybody know if this is a bug in Jira, or how can I work around the issue?

Edit; Extra info about attachment configuration:

Allow Attachments = ON
Attachment Size = 10 MB (file size is max. 75 KB)
Enable Thumbnails = OFF
Enable ZIP support = ON

Dennis van Beek · Accepted Answer

The problem was in the filename.

Thunderbird saved it as `Re: xxx.eml`, the colon caused the problem.

In my opinion not a very descriptive warning message, especially the one for the individual attachment. It would have saved me hours if the message was a bit more descriptive (and correct).