SASL LOGIN authentication failed

[mike_]

Hello
I've ZCS 7.0.1 Open Source running form Linux Centos 5. The email server is worked ok but have one problem with sasl. When I configure user account (outside my network) whit pop3 protocol in client MSO and I check "My server requires authentication" and try send email remains in the outbox and appears in client the next error:

 your server no support  the authentication methods supported by this client are supported by your server.

When i'am inside my network I have mandatorily uncheck "My server requires authentication" and try send email the process is ok, but i'm not authenticating. I need setting any aditional parameter ?

best regards