Xiaomi's mobile phone is connected to the campus network, and the portal server can't get the device information or the device doesn't respond to the req-info message.

Portal can't get the device information, which is a problem with the wireless network provider's device. When you connect to the campus network, first, the mobile phone is connected to the router, and the router judges whether it has permission. If not, it will jump to the authentication page of the portal server, and the portal server will query the IP/mac address and other information of the mobile phone through the req_info command, and then authenticate.

Your problem here is that when the portal server asked the router for the corresponding information of your mobile phone, the router didn't return it, so it reported an error.

Solution: Because the router didn't return the relevant information of the mobile phone to the portal, it is likely that the router didn't get the relevant information of the mobile phone, and it is likely that there is something wrong with the message sent by the mobile phone. At this time, clearing the cache or restarting the smartphone should solve the problem.