iPad not showing up in Configurator

I have an iPad 2 that shows up in iTunes but not Configurator.

I've tried it in Recovery Mode, I've reset it to factory defaults, I had iTunes restore it to a previous backup... no matter what, Configurator will not see this iPad. It never shows up in Prepare or Supervise.

As a side-note, I've been having major issues with iOS 7. I'm on Configurator 1.4 and iOS 7.0.2. This issue was happening with 7.0.0 and upgrading to 7.0.2 made no difference.

Is there a way to remove this iPad from the configurator database? I was using it previously but now it isn't seen. I thought maybe the iPad's name or serial is in limbo in the database or something.

Any help is appreciated.