There are several factors to consider for proxy connections:
1. Check if you are using a proxy in an overseas condition.
2. Check whether you have entered the wrong proxy address: port: username: password.
3. If you are copying and pasting the HOST file to a computer or server, please verify that there are no extra spaces.
4. Check that you have selected the correct network protocol .
5. If it is charged by traffic type proxy, check whether your account balance is insufficient .