Unable to connect to world

Hi,

My brother and I are attempting to join each other's world on iPhone with no success. We are on the same wi-fi network and have attempted working through all the online suggestions. 

>deleting the app and re-downloading

>restarting phone

>deleting are re-adding as friends

>wiping mobile data/browsing history

>checking xbox live settings

Whenever we try to join each other's world we received the unable to connect to world message. I am contacting you because I think the game needs development in the area of connecting to friend worlds. There are a lot of reports online stating the same issue with no clear resolution.