[Dovecot] Dovecot doesnot disconnect at end of pop3 session

[Robert JR]

Hello,

I have 3 users checking same email account using pop3 (outlook express)

suddenly after some hours , users are unable to disconnect from pop3 
after checking mail

So i telnet to the pop3 and found that the issue is true but i do not 
know the reason

telnet mymail.com 110
user username
pass password
list
quit

all commands work except the quit command, Dovecot hang at this point 
!!!

Why Dovecot hang on receiving the Quit command !!! and doesnot 
disconnect !!

Any help is greatly appreciated.

Thanks.