My Version via STEAM:
aoeliverelease age4 8.1.276.0
I have the problem that I´m not able to achieve any new mastery with every nation.
Plus the mongol villagers can´t mine gold.
Could please somebody please help me.
Thank you
Which specific mastery cant you obtain?
It is impossible to obtain with every nation.
Osman/Malier the first mastery
Holy Roman Empire/Rus/ Abbasieden the 6th mastery
China the 8th mastery
Delhi the 10th mastery
Mongol the 7th mastery
England and France are already finished
I just made a fresh installation of the game, but the bug is the same.
I just did the Mastery with HRE the last few days, this one works. I can confirm the Mastery with China, that really pisses me off. The others I have not yet tried.
I just tried the HRE mastery after I read your commend.
Still doesn´t work.
Maybe you are doing something wrong? At least it worked for me 
There is no problem in completing this task, maybe you are making some mistakes somewhere that you don’t recognise. Remember also that there are certain limitations, especially when it comes to the nation, you have to gain a certain level of dominion there.