This.
Authentication has nothing to do with where your character is stored.
You create your account in EU, your authentication information will be handled there. period.
You select US account, cool so your character will be stored and accessed there AFTER YOU ARE AUTHENTICATED.
Authentication services 101.
Patience folks.
i ve never played wow on EU, and i do have the same issue since today manteinance. I do live in Europe, but my acc was created in us servers.
same here …wow51900123
I have literally never been on EU, lived there, or had anything to do with EU. (NA for 15 years) and this is happening to me so please stop telling us its an EU thing. Thanks
This stuff keeps on happening and yesterday Tichondrious was down for like 2 hours and was the only server down and i sent a ticket and they opened it and straight up ignored it… this is getting really frustrating especially this issue where u got no clue whats going on
If you had let me transfer my account to the US it wouldnt have been an issue then 
Hopefully fixed soon
My friend in the US asked me to join her ingame and so I let my EU account go. Nothing unusual for the gaming world at large, but something technical has obviously happened as a result.
Darn and I was looking forwards to levelling a couple of alts tonight.
Same here, what kinda bothers is that I just paid the 15 bucks to play the prepatch and barely could connect for a couple hours last night before maintenance…
hello i still get dc after dc too cannoct connect at all
everytime since yesterday i try to play something is broken hope blizzard will do something very quick
Can t connect at all !!! HELP US PLOX
Still happening - still awful.
I’m also getting these errors now after trying to change characters and I play on a US account that was made in the US.
Seems servers are acting up again.
I feel your pain. I have 4 collectors editions sitting on the EU from vanilla onwards. Vanilla in particular hurts! 
Same 
and so many store mounts
I think to be compensated those of us who cannot connect should receive a lifetime sub. Seems fair.
personally i’d be okay getting all the mounts/items/achievements ported over from my EU account to the US account (same bnet account, surely this can be replicated?)
also, MANAGED TO LOG IN GUYS! ty blizz 
What a coincidence , they shut the Paris office and boom problem with EU accounts …(mainly ) perhaps some disgruntled staff !!!
Posted on Bloomberg.com 6th October staff were told , they would be informed a week later … 13th October … hmmmm
Video game publisher Activision Blizzard Inc. informed employees in its Versailles, France, office Tuesday that the location will be closed, putting an end to the U.S. company’s history in the country.
The Versailles office employed about 400 people as of early 2019 and handled marketing, customer support, localizing games to different languages and other functions for the titles Activision Blizzard publishes in Europe.
The company originally planned to relocate half of the office to London, according to the people, who asked not to be identified discussing private information. However, the twin factors of Brexit and the coronavirus pandemic have inhibited that process, leading to the decision to shutter the site about an hour’s drive outside Paris.
Staff members were told that they will learn more next week. A spokesperson for Santa Monica, California-based Activision Blizzard confirmed that management has informed its employee representatives of a plan to reorganize its activities. “Over the past year we have been exploring how we might best integrate our capabilities across the business, enabling us to better leverage talent, expertise and scale as we adapt to the needs of a fast-paced, highly-competitive, digitally focused industry,” the spokesperson said.
I changed classic language to spanish, and it finally logs in. I’m still downloading the language pack in retail.
Working again for me too, back to Wrath to level!