Multiplayer is not working on mcpe

Everytime im trying to play with my cousin Minecraft pe, it doesn’t let him join, he restarts Minecraft but stills doesn’t let him, and we are connected to the same wifi but when he’s in his house it does let him join my world, but when he’s in my house it doesn’t and this has been going on already for 2 months please help fix this, or is probably a glitch/bug

Thank you.

:)