What is my fault on POP3 authentication

[dstuncer]

First I appologies my poor english.
I installed Zimbra 7.1.2_GA_3268 on UBUNTU10_64 FOSS edition and created 4-5 domains, add some users for each domain. Everything is ok. Every domain member can send and receive mail on zimbra web interface but can not use from outlook or other mail software. Wrong User Name (0x800CCC90 0x800CCC91) error mesage replied. I used user@domain1.com for user name, it works on web interface. POP3 port 110 and SSL not checked and clear text login checked, SMTP port 25 and also SSL not checked on zimbra server.
Many thanks for your helps.