Guests can´t enter the caves: server is not responding.

Hello we ve got problem with my friends that guests on host server cannot enter the caves resulting in loading and then message server is not responding.
This happened after 1.12. This is like we can´t play this game anymore w/o caves bugged and i found so many old threads and posts with this problem so can u fix your game and make things work again ? We are really sad that caves are not working anymore for any who join the host game ....
Tried everythin like firewall exclude and run as admin, with no mods, etc.... still not workin:
We all bought the game with expectations its fully workin with support and bugs repairing and not this :c its my the most favorite game so pls fix your game so everyone with this issue can play again with full experience game and not half.