How to fix error 51900101 in World of Warcraft Classic?
Error 51900101 in World of Warcraft Classic is an unmotivated disconnection from the server and, as a result, crash from the game. This problem cannot be called new, it exists for a long time and is eliminated by a time-tested method.
To do this, simply delete the WoW Classic cache file. However, if the information that is stored there (for example, the keyboard layout and personal settings of the interface), then it is better to write down everything before deleting, so that then you do not have to remember for a long time. You need to find the Classic folder in the game folder, in which Cache is stored. We delete it, having previously closed the game. Then we start WoW again (the folder will be recreated), restore the settings and continue playing.
If this method does not help, it is recommended to double-check the connection (restart the router and the computer), and check that the Windows firewall and / or antivirus do not block the game.