I can't connect to a realm created by a friend, and this issue only seems to be related to his particular server. I can connect to the featured servers and my own single player worlds. The realm is called "Connexas" and was created by the xbox gamertag "I Oaka XXIII I" (the I's are upper case i's). I only have this version of minecraft on my Xbox One and my gamertag is Pebbles747. Connexas is a two person server in survival mode on normal difficulty.

The realm allows me to join, and then varies on how long it takes before booting me from the game. Typically I get to Realms: Building terrian and then get disconnected from server. Once I actually got into the game but was immediately kicked upon the build. The disconnect initially occurred near a blaze spawner farm I had created in the Nether.