I’ve found a “solution”. The problem was that I saved a game during a custom campaing, apparently, there is a bug that prevents progress if you continue a saved game during a campaign. Here (Ottokar campaign not Advancing past first mission - #2 by CanineCrown7153) a guy says that.
I tried and it works, alas, no saving during a campaign, I have to beat Magyars and Bulgarians without saving 