I believe that you run into issue with empty return-path info from your mail server.
This is 1.1.1 regression issue and any time soon (this week, I expect) must version 1.1.2 be delivered.
You can temporary:
- switch to another mail client (if it's possible), like GMail
- configure your mail server to send return-path info always
Sorry for inconvenience.
More details about issue you can find here:
Yep, I am facing the issue noted in the link you have below. Any idea on when the patch will be released?
Kevin M Reddish, CISSP, CEH