There are 4 other family members in my xbox live family. 2 of them can access the Realm from a PC and play on it just fine. Whenever anyone tries to access it via the Xbox One however, they do not have the option to join. The option is instead replaced by a message that states 'We could not connect to Realms right now. We will try again soon.'

Restarting the console from settings appears to fix the issue, but the console must be restarted each time