Classroom Manager Issues loading students

I am really wanting to use the Classroom Manager, especially now that Chromebooks can be accessed. We use Chromebooks and I teach Visual Arts and I was so excited but when I loaded the Google Classroom class and the system sent out invites, my students didn't get them. Our IT person made sure that the had the permissions on the back end of firewalls etc. adjusted in order for the emails to be received. I then had them sign up through the class code. Many of my students received either an "OOPS this appears to be something on our end" or "Documentation Required" when I know for a fact that all IT requirements have been met. So I still can't get them signed up nor use the Classroom. So I need help and need it fast. Thanks in advance!