Just restart the game. If it doesn't work, just restart the computer. This is usually a problem with the official website of the alliance.
This problem often happens to me because my home network is connected to China Tietong Network and I have never had this problem in school. So this is a network problem, because Tietong Network always The IP changes every time you connect. It is not a fixed IP address. My home IP is sometimes Nanjing IP, sometimes Suqian IP, and League of Legends officials will think that you are hung up, so this often happens, and there are unknown errors and login failures. So it is definitely a network problem. It is recommended to restart the router. If it still doesn't work, open the IE browser-Tools-Internet Options-Advanced and check the "Allow running or installing software even if the signature is invalid" check the box. Try it. Bar. .