I can't login in game after character selection menu

Today I accepted an invitation to a guild, and immediately after that, I lost control of my character. I realized this because I couldn’t do anything in the game: the client wasn’t sending any actions to the server or receiving anything back — the world seemed to have "frozen."
Next, I used Alt+F4 to close the game and tried to log back in, but since then, I haven’t been able to access my character. If I try to log in with the character where I accepted the guild invitation, the loading screen goes on forever. If I try to log in with other characters on the same account, the game shows the loading screen and then drops me back to the character selection menu with the error "Login failed."

Any suggestions on how to fix this? I already reset my character through the site menu, but it doesn’t seem to have resolved the issue.

Disable addons - if that fixed it, find the faulty addon and uninstall it.

Did try. Doesn't work disabling all addons. Also cleaned WTF and Cache folders.