Title : Mbsync and imap login problem Author: Solène Date : 17 May 2016 Tags : solved email I have not found any answer about this so I share my fixed. I wanted to use mbsync with one IMAP server and encountered the following error. IMAP command 'AUTHENTICATE DIGEST-MD5' returned an error: NO Authentication failed A fix is to add the following to your ~/.mbsyncrc IMAPAccount declaration. AuthMechs LOGIN Using LOGIN instead of DIGEST-MD5 is still secure **if** you have an encrypted connection (IMAPS or STARTTLS). The login will be given plaintext inside the connection.