Trying to get Round robin going here on a few keys... E T and Q at first.

I have them selected in the Round Robin section of setup.

I click the round robin enabled key, I hear a computer error beep, and nothing happens.
I click the round robin enabled key again, I hear the beep again, and both (only trying 2 at first) clients cast the spell.

Neither of the account is selected to disable round robin.

Any clues?