Authorization error with Digital Editions

My computer died, so I restored a backup onto new hardware.  Digital Editions installed, but won't work.  When opening an ebook, it says "Error! Check activation"

Help->Authorize Computer is greyed out, implying it's already authorized.  

I tried Help->Erase Authorization, but that fails telling me "try again later".  

I'm running the latest ADE, 4.5.11.

Any guess how to fix this?  I've tried following the support links and Contact Us links, but they are all either dead links, or lead back here.  Any help would be much appreciated.

Thanks.