1, the proxy server address or port number is entered incorrectly. You need to confirm that the address and port number of the proxy server are correct, or try to replace another available proxy server.
2. The proxy server is unavailable. The proxy server will be in a maintenance state. At this time, the device cannot connect to the network through the proxy. You can try to replace other available proxy servers and ensure that the current proxy server is in a normal state.
3. The proxy server needs user name and password verification. If the proxy server requires authentication, please ensure that the user name and password entered are correct.