An Adobe Digital Editions error has been detected. The maximum number of machines allowed per ID has

I have a Kobo libra H2O e-reader and everything has been fine for several months.

Recently, when I tried to open a book with my Kobo eReader, I got the message "your reader is not allowed to open this book ... please authorize again.

So I deleted my authorization BUT when I tried to authorize my eReader again

ADE's Adobe ID contains a lot of letters and numbers.

The Adobe ID of the eReader is: Adobe ID    (default ID)

When I click on "authorize device", I get the message:

An Adobe Digital Editions error has been detected. The maximum number of machines allowed per ID has been reached.

I spoke with several people at Adobe, a technician even took control of my computer to try to fix the problem on my computer but nothing to do.

Can someone help me please. Thank you.