Game is running + login loop error

just downloaded the game and my first problem was trying to launch the game. after a lot of tries with suggestions by blizzard website and forum (none of them really worked) and some minutes of research, found at reddit that if you launch offline it works, and it definitely worked. managed to play yesterday night, but today i got stuck on “authentication” and can’t login. do you guys have any suggestion?

it’s kinda frustrating seeing all these errors in a game that once was really respectable. just wanted to remember my WoL days laddering a while but seems that i wont be able not even to do that.

update: managed to log in US server, EU not working