My friends cannot join my worlds

My friends can't join my worlds, regardless of the account or the platform I use (tried on my phone, on wifi and 4G). I can't join most of their worlds too. It's says unable to connect to world without any error code

My friends either play on Win10 or Switch.

 

I also couldn't join a world of someone I don't know the platform.

It started in augustus or even before, as I wasn't able to play since mid-july

 

this is really annoying since I love to play multiplayer creative or some survivals with my friends

please, help me.