Hello Guys!
Thanks so much for all the support, i was able finally to log in with this Solutions
there are several solutions for the error BLZ51901001, you can find them here: Firestorm Forum | Error BLZ 51901001 Firestorm Support | Error BLZ51901001 Firestorm Support | Error BLZ51901001 #2
Also moved the topic to the Legion category.
But now, when i try to log in to the server i receive this error.
Screenshot attached
Thanks @Qalmir