Xbox.com has limited Access you cannot search for players like you can on Xbox One, the recent players option has the same error constantly which is can't load. I would advise doing this on the Xbox App.
Since my last Comment i can confirm that it's not possible to do this from Xbox.com anymore, the Way i Discovered is just Add people from your Console then Erase them from the Xbox App.
It's a Shame that the OP has Abandoned Updating his Guide or at least replying he was Last on this Website on September 19, 2020
