WoW: error BLZ51914403 blocks logins through wow.exe

Since the night of 23 to 24 September, players report that World of Warcraft disconnects them with the error BLZ51914403 when they start the game straight from its program file, such as wow.exe, and type their email and password into the game's own login screen. Starting the game from the Battle.net app works, they say. The reports come from Blizzard's European forums in English, German and French and from its American forums. Players name the main game (Midnight) and Classic versions including TBC Anniversary, and 2 players say it also happens with the beta client. A player on the French-language forum links the start of the problem to a game update on 23 September; Blizzard has not said what caused it.

On the afternoon of 24 September, Yryadorne of Blizzard's customer support replied on the European forums in English and in French. The reply says Blizzard is looking into the issue, which seems to affect players' ability to log in when using wow.exe. Logging in through the Battle.net app seems to work without problems, and Blizzard encourages players to use the app for the time being. The reply does not say what caused the error or when it will be fixed. The largest thread on the American forums, with more than 60 posts, had no reply from Blizzard by 22:00 on 24 September, Central European time.

Players who have always signed in inside the game explain why they do it. Several play with 2 or more accounts on one computer: to run the main game and Classic side by side, to play alongside a partner or a sibling on the same PC, or to run several characters at once. Without signing in inside the game, a player has to sign out of the app, sign in with the other account and start the game again each time. Players on Linux, who run the game through compatibility software, say they start the game file directly because the app works poorly in their setup, and a few other players say that starting the game through the app causes problems on their computers.

Players are passing round a workaround: an option at the bottom of the App section of the Battle.net app's settings lets several copies of the app run at once, each signed in to a different account. A player who turned it on quotes the app's own warning that this will almost certainly cause strange things to happen, and at least one player says it did not get them in. One player says clearing the game's cache folder fixed the error for them; several others say it did not help, and neither did reinstalling or repairing the game.

A few players on the American, German and English-language European forums say they cannot get in through the app either; Blizzard's reply does not cover that case. A few of them say the app let them in once they deleted a text file in which they had saved their login details for the game. Other players fear the change is deliberate, a push towards the app. Blizzard calls it an issue it is looking into and has said nothing more.