You need to know the network domain. The easiest way to find this at school is to log into a machine and right click on the network connection, open network and internet settings. It should show the domain. If not, then open a Command Prompt and type ipconfig. The "Connection-Specific DNS Suffix" will be the domain, make sure that whole name is in the "domain" section of the login. Before Android 11, I never had to input the domain.