Disconnected immediately (BLZ51914400)

Hello, this occurs when launching the game through battle.net - Cataclysm classic
I played about 12 hours ago before the pre-patch went live and it was fine.
Tried flushing dns, restarting ONT + router, deleting cache folder, restarting PC.
Tried launching the game without battle.net - same issue
I open the game - 1 second of “Connecting” and then the error appears.
I am currently running a “Scan and repair” but wanted to report this issue in the meantime since its taking a while.

Hope to hear from you
Regards

Update:
Scan and repair did absolutely nothing, a waste of more than 2hours
I completely uninstalled the game and installed it again (way faster than scanning and repairing in hindsight) and I have successfully connected

I’m having the same exact problem, I did reinstall the game but unfortunately it did not work. May I know how did you uninstall it? by the B net launcher?

Through battle net and then I deleted the leftover folder