Hi all! I have a new problem about POP3 service. After create a new email account in Cpanel, i have check successfully on webmail, sending& receiving are very nice But when i use Outlook Express to check mail, there is a problem. Because SMTP server and POP server are installed in only one server, i enter the IP address of server for SMTP&POP3 server parameter in Outlook, insert username and password and done...... Click send/receive in Outlook, it notice Account: '18.104.22.168', Server: '22.214.171.124', Protocol: POP3, Server Response: '-ERR Authentication failed.', Port: 110, Secure(SSL): No, Server Error: 0x800CCC90, Error Number: 0x800CCC92 and i can't login to my email My SMTP is Postfix, POP3=Dovecot, I have config all as the same as guide tutorial. telnet at port 25 and 110 are good, these services are online.Also checked " Mail dir" in ISPConfig Setting Additionaly, each account mail is a real user of OS. What the way we can use as virtual user? Real user is not good in security aspect! Thanks for your help!