An Invitation Problem

Greetings! I am a superadmin of Open Discussion ("OD") and of MindWalk's Truly Open Discussion ("MTOD"). I am having a problem that I don't know how to resolve. A user sent me a message asking to be invited (actually, he should be able to waltz right in without being invited, but it doesn't seem to be working for him to do that). I scrutinized--and I do mean scrutinized--the member list, saw that he wasn't on it, and went ahead and sent him an invitation. Or, alas, tried to. When I hit the "Send" button (or whatever it's called), a banner appeared at the top of my screen telling me that he was already a member. And the invitation wouldn't send. I do not know what is going wrong. Has anyone else encountered this sort of problem? Does anyone have any idea how to fix it?

Is he possibly on your ban list?

No. I never banned anyone (I would have, but the user left, so I didn't have to), and my co-superadmin tells me that he didn't ban the user in question, either. And the banner message I get is that he's already a member. 

Do you know how to check your banned list to make sure nobody else banned him?

Ah! Problem solved. I didn't know how to check the banned list. But once I figured it out--there he was! I don't remember having banned him, but maybe my memory is faulty. Or maybe my co-superadmin did it in my absence. Anyway, I've unbanned him and sent him an invitation, along with a reminder to abide by my rather liberal (in the nonpolitical sense) standards of reasonableness and civility.

It would never have occurred to me that a *ban* could have resulted in a banner saying that he was already a member. Thank you.

So how does one find the Banned Members List?

Click on Manage Club --> Ban a Member.   A list of banned members is there.

Yes, under the hood, banned members appear to be considered club members who don't have access to anything.  This has resulted in some (now fixed) bugs in the past - for example, once it was made so that you could ban people not part of your club, someone discovered that you could ban and then unban people to force them into your club; that has now been resolved.

OK. Thank you eulers_knot and MGleason.

Helpful information here. Very good to know. Thanks for bringing this up and thanks for everyone who answered intelligently and clearly.