cannot join parties

Hey,
started playing two days ago and noticed that I can't join or form parties sometimes( msg about confimartion to join is popping but nothing happens after I accept).
Tried restarting game+ launcher mutliple times, changing channels, switching characters, restarting router and nothing helps

I'm playing from EU if that makes any difference

 

Did you by any chance forget to leave an old group?

 

Someone who had this problem before was able to fix it by going to the black desert online folder and deleting the cache file.