I have a Problem that doesn't join me my son using local network. (Same Access WIFI Point)

I've played very well my family on the same internet recently.

Suddenly, They didn't join my world. I mean they joined my world, but they didn't join my world. 

 

They were waiting continuously for a very long time.

 

so I think it's a huge bug in my map or game.

 

I attach some files that are screenshots and log files.

Please Help me and fix it.