I tried to add my partner @ stormpelt and sent a friend request, but on his end he got unknown error messages when trying to accept it. We both found in the "friends" sections of our profiles, we had the same issue where the initial page said we had friend requests enabled, but at the "pending requests" section, it said we had them disabled. We both tried to change our settings from there, but he still got an error message saying that I had requests disabled when he tried to accept mine. If it's relevant: I had been playing on the legacy version of the site without logging in the preferred way when I sent the request, then switched to the newer version.

In your dashboards, under preferences, look for "Allow friend requests." Is it checked or is it empty?

I hadn't seen this setting before, but it is checked.

That's odd but at least eliminates that as a potential reason.