samba - Jul 2015 - Problems with workstation in Samba 4 Domain

I'm using Samba 4.2.1 on my network.

I configured and put a computer in the domain, after i created an image of
Ubuntu 14.04.

In followed i installed this image in the many computers, but i had
problems with the user's authentication, that i solved putting the
computers in the domain manually.

The fact of i create a image of a computer already in the domain and after
have to put the computers in the domain manually can be a problem?

How i verify if all is correct?

thanks!