Here’s a very strange and interesting bug (that was resolved pretty quickly), as EU Classic Era players were receiving the “realms will be unavailable in this region from January 23rd, 2023” message today, that was meant for the closure of Chinese realms earlier this year.

This issue did not affect all players on EU servers, but there were plenty of reports, and Blizzard did hotfix the problem fairly quickly (around 1-2 hours) after the first report.

Hotfix (Source)

Hi there u/Prodooc. Just stopping by to let everyone know that the WoW team is currently aware of this issue and working on getting it resolved! No ETA at this moment, but they are on it.

EDIT: Ok they have already fixed it! If you are still having any issues please restart your Battle.net app and check for WoW updates before opening the game.