Can't Join Lan world

I start a world on my Nintendo Switch and want to join this world with my Win 10 bedrock version and the error "no connection to the world" appears.  After that I made the effort to install all non-important updates to my PC and I still couldn't join with the message that the world was full even though only 1 player was online.  I have the same problem when I want to join the world with my mobile phone (Android 8).