When sending invites to friends from a single player world on Invite only sometimes Invites do no pop up for the person being invited. They will not see it on either the Xbox console Companion or in game on Minecraft. This bug has been around for a while now but it dosent look like very much information was ever put out so please take note to the video link. 

*Suggestion Make invites the same as Realms where the receiving player gets a little envelope on the main menu