Dovecot Authentication failed if trying login with @domain

问题

When I try to test my IMAP server functionality using telnet I encounter the following error.

If during the test i omit the @domain.ex everything works fine(as you can see below);

a login user password
a OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT 
SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL 
CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC 
ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS SPECIAL-USE BINARY MOVE] Logged in

if I try using username@domain.ex. I receive the following error:

a login user@domain.ex
a NO [AUTHENTICATIONFAILED] Authentication failed.

Someone knows where i'm mistaking ?

Thanks in advance.

来源：https://stackoverflow.com/questions/25817049/dovecot-authentication-failed-if-trying-login-with-domain