[Dovecot] Problem Authenticating with Master User

[Henry Franco]

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 at server.com*master my_password
1 NO Authentication failed.
1 login user at server.com*master my_password
1 OK Logged in.