Why does "Request Access" not appear in Onedrive for Business?

[Windows Central Question]

I'm sharing some files using Onedrive for Business. Most users that I have given permission to have a "request access" link on the ?Sorry, this site hasn't been shared with you? error page when they try to access but one user does not. He has sent screenshots showing that that link does not appear. But his id has been given permission.

I can't find any reference on line or in help that explains this. Can someone enlighten me?