Daniel dude it is fortnite since they are the ones that caused the issue to happen in the first place seriously I have confirmation from them that they are aware of the issue and said it would be fixed next update. I have cross play on as I don't always play fortnite and play call of duty so if it was xbox then I wouldn't be able to play call of duty.
Hmm epic games can add a new mode in fortnite called sleep mode but can not fix an issue on xbox that says cross platform play is currently disabled. Been having this issue and yet if epic games are aware of it then why not fix it instead of adding new stuff.