Problem with fresh Kolab setup

[Jekabsons, Matiss]

Hallo!

1. i have Ubuntu 14.04 server
2. on clean server, installed Kolab
3. created one user (i am using that user email addres right now, with 
this email) - success...and all working just fine
4. i can create new users, but when they log in, they get error msg, 
that mailbox does not exist.

Googled, found some, but none real solutions that works.

Any sugestions?

Thx
Best regards
Matiss