https://wiki.archlinux.org/index.php/OfflineIMAP#SSL_fingerprint_does_not_match http://blog.developwithpassion.com/2014/12/18/quickly-fix-offlineimap-ssl-fingerprint-error-in-tmux/ however you really *really* should be making absolutely sure that you're not being subjected to a man-in-the-middle attack. l.