Hello i just got this message and disconnect
“You have been disconnected because your account information has changed. (BLZ51900062) ”
I never saw this error so dont know what happen or what to do. I have ultra strong password, physical authenticator bought in 2012 (yes still working) and phone protect. Nothing was changed in my account and i can log in back.
No suspicious logins as well? Authenticator and SMS protect still on?
Could be back-end works, but it requires a CSFR to confirm tomorrow.
I just got the same, ~5mins ago.
Same happened to me about 30 min ago
I got the same error message 5 minutes ago.
It happened to me and my friends we got disconnected 1 by 1, maybe blizzard could atleast inform people… but we do not pay for the game, its fine.
Same just happened to me, was idling in Orgrimmar on an alt. Suddenly error BLZ51900062.
Happened to 4 people so far during our reclear tonight. What is going on, Blizzard?
I got the same today on multiple accounts at once, what is this?
Blizzard please inform us whats going on.
keeps Dcing us on in the raid as we’re trying to prog.
Same issue here, no email regarding any changes to my account information though.
Just happened to me to!
Can’t login now.
Multiple Guildies have had this tonight when we are trying to prog 
I got disconnected from WoW Classic Era with the same message and checked on the website but I don’t see any changes in account information. However, I have noticed that my Battle.net balance is now showing 0 with nothing in history to indicate what happened to the funds.
Battle.net says that i haven’t played since Januari 15, and that i haven’t payed since 2020!
My battle.net ballance have been drained, its now 0.00
So I’m not the only one. I guess it might be related. Did your Battle.net store currency also change recently?
Yes, from Euro to SEK.
This many people getting the same message…sounds like backend maintenance to me, probably something to do with the payment systems if currencies are randomly changing, balances appear to be missing, and transaction histories are incomplete.
You´re almost certainly all going to be fine in a few hours. 
Or you all paid with stolen credit cards, lol. J/k, ofc.
It seems serious while its happening but again, worst case scenario the backups get restored and the maintenance gets pushed back until they can suss out the issues.
I have had the same twice tonight, last time just a few minutes ago.