Well, I have encountered this situation in the past, probably because the school reorganized the network structure and excluded the network of the student dormitory from the school intranet. You can check your own external network IP to see whether it is an education network or a school IP, which is likely to become xx Unicom and XX Telecom. The public account of your school in HowNet can only be used by users of the intranet. Of course, you have to enter a user name and password to log in to the IP of the external network.