[Dovecot] Problem Authenticating with Master User

Dovecot provides a master login (a master user name and password that can log into all user accounts).

I've setup Dovecot as per: http://wiki1.dovecot.org/Authentication/MasterUsers

Here's my problem.

The only way I can authenticate successfully is if I try to authenticate through telnet twice. Also, imapsync (the tool I need to use to migrate over emails from Dovecot to other mail server) won't work because of this.

$ telnet mail01.server.com 143 Trying 10.10.10.12... Connected to mail01.server.com. Escape character is '^]'.

• OK Dovecot ready. 1 login user@server.com*master my_password 1 NO Authentication failed. 1 login user@server.com*master my_password 1 OK Logged in.