I am migrating my companies intranet from a OS X server to an Ubuntu 12.04 server. We use a flat file to store user names and passwords hashs. This file is used by Apache and Dovecot to authenticate users. The Ubuntu server is running Dovecot 2.0 while the OS X server is running Dovecot 1.2. I have already migrated WebDav which uses Apache for authentication. Authentication works. I'm in the process of migrating our Prosody server which uses Dovecot for authentiation. Dovecot is up and running, but when I test authentication using either telnet a login username password or doveadm sudo doveadm auth username, I get dovecot: auth: passwd-file(username): unknown user dovecot: auth: Debug: client out: FAIL#0111#011user=username in my log file. I can use sudo dovecot user username to perform a user lookup and it will return the user's info. I can generate a password hash locally and Dovecot will authenticate the test password just fine.