Macbooks won't connect to Apple Classroom

We use Apple Classroom to manage iPads and the Macbooks in my Digital Art Lab. Our Apple Classroom pulls from our student enrollment in Powerschool. For the most part, we have no problem with their iPads connecting when I activate their Apple Classroom. When they log into their computers, only a few of them are showing up. I have checked that their bluetooth is on. Is this a setting in Apple Classroom that needs to be changed on each computer or could be a communication error between Powerschool and Classroom? I do not have the ability to add students because of the way we have is setup. Any advice?