Unable to play multiplayer

Dear Minecraft Team, 

I purchased this game on my phone not only to enjoy the game but to also be able to play it with my friends and family whenever I want. The game keeps telling us every time we send an invite or try to join our friends world that it’s “unable to access world”. We’ve tried changing the settings, we’ve even made sure to be under the same WiFi, check the speed of the WiFi which seems to be working good, and after multiple times of trying the game finally let us play together but then my friend accidentally got out the game. Now it won’t let the rejoin again or let me invite them again by once again saying “unable to access world”. Please help us resolve this so we can play together as it’s one of the biggest reasons why we paid to get the game on our phones. 

Thank you in Advance.