Onedrive sharing not working for one user

There is only one user who cannot share with anyone external or internal. I have checked everything, they are a site owner, a site admin, a site member, we have no restrictions on sharing, it works for others. I made a new site just for them as the only admin, they still cannot share. They have been removed and re-added 5 times. We have a microsoft support ticket and they don't even seem to know the issue. What can I do?