Character somehow doesn't have an authenticator attached?

I have two wow accounts and made a private guild for all of my toons on one particular server. I have one toon on one account as the guild master and several toons on the second account as officers. However, one toon I just invited can’t be promoted to officer because it says she doesn’t have an authenticator attached to her account. None of the other toons on the same account are showing this issue. Also, this toon has the extra bag slots that you get for having an authenticator so it was recognizing it on her at one point at least. I tried logging out and back in and kicking the toon from the guild and reinviting. Very strange issue.