Cisco MDS Refuses to Authenticate to RADIUS Server

I have my switch configured to use a RADIUS server for remote authentication. If I log in with a local user, I can prove the authentication to RADIUS works with the aaa test command. If I try to log in via Device Manager or Putty, remotely, it doesn't even try to use the RADIUS server. I can tell this by getting the transaction count. If I understand correctly, It should try the RADIUS server first, then if that fails, it should try locally. What could be causing this problem?

Thanks.