Glo Content locked

I recently tried to open a half-dozen or so books in the Desktop (PC) and got a message "Content locked. We are unable to display the selected content. It may be locked or corrupt." I sync'ed a couple of times, but keep getting the same message.

The books open fine with my Glo and my Samsung tablet.

Desktop version 3.5.0
Glo 3.1.1
Android 5.1

Any suggestions for a fix would be appreciated.

Thanks,
Tom