When I try and connect to my freinds world it works but they can connect to me

Steps to Reproduce:

I go on my world.

invite my friend and they join

their Minecraft says unable to connect to world 

Observed Results:
I go on my world, then my friend joins in the friends part but after that it says unable to connect to world.

Expected results:

it should just let him in

Notes: 

i am playing offline and my friend is on android and a windows 10 laptop it would be REALY nice for it to be fixed.