How to fix the Unable to Connect to Authentication Server error in League of Legends

gamepur.com:

Many League of Legends players has been hit with an error message that reads “unable to connect to authentication service.” The issue may come from either a bad internet connection, a disruptive firewall, or could be an issue on Riot Games’ end. Players will get the error message either during champion selection, at the login screen, or halfway through a game.

Fortunately, there are ways to fix this problem on the players’ end. But first, a player should check Riot Games’ Service Status webpage to see if there have been recent issues or reports about the server they are trying to use. If there is nothing wrong with the server, then the problem could be the Windows Firewall.

If a player hasn’t updated their Windows Firewall, it can prevent the player from accessing the game correctly. So the player should either update their firewall or temporarily disable it. They can find the firewall settings on the Windows Security window. Players can search for Windows Security on the search bar at the bottom of the dashboard. Players can turn off the firewall for the Domain Network, Private Network, and Public Network.

Another troubleshooting option is uninstalling and then reinstalling the game on the PC. A complete reset could fix whatever issue that game was having internally. Turning on and off the wi-fi can also potentially fix the problem.

If none of that works, then players should contact Riot Games’ customer support.