Unable to download ebooks from Borrowbox

Hi

I'm using Borrowbox on my windows 10 laptop and borrow ebooks from the library. I've never had any problem downloading books to read on my Kobo ereader, using Adobe Digital Editons 3, but I'm now getting an error message as follows:

Unable to download

Error getting License. License Server Communication Problem

E-AUTH-BAD-DEVICE-KEY-OR-PKCS12

I've also tried using Adobe Digital Editons 4.5.11 but get the same error message.

I'd be very grateful for any advice you can offer on how to resolve this problem.

Thank you very much