I am currently out of ideas!
Thanks for reporting back that it didn’t work. It was a good idea to try changing the options>general>data> online settings to OFF, saving and then closing MSFS. Restart MSFS and then turn it back on.
If I get any more suggestions I will post them here.
I do recommend (if you haven’t already) filing a ticket with Zendesk, saying it is affecting your account on both xbox and pc.