Unable to sign into fortnite and rocket league

My son is unable to sign onto his fortnite account and hasnt been able to sign in for months. The error message on screen is 'Unable to sign in to your account for xbox live. Please try again later.' We have tried uninstalling and reinstalling fortnite but we still get the same message. When trying to play rocket league with friends i get the error message saying 'having problems communicating with epic online services'. We've tried all the suggestions online and have even reset the xbox. I spoke to epic games and theyve checked his gamer tag and all is good with that account. Can anyone help me with this issue please?

:)