A new Apple Classroom has been created (this week) 
and after the student has been invited to join the class and added the four-digit code, an error message appears saying: "5A" has expired and will be removed. Classes that have not been joined for more than a year are automatically removed. This is only happening for one student. We have done all the basic troubleshooting (e.g. hard shutdown, forget the network and rejoin, check "trust certificate", configure the proxy), but no luck. Any suggestions?
