Document licensed by different user account

Hello,

have reinstalled Digital Editions after quite some time and wanted to open some of my eBooks.

I get the following error (liberal transaltion):

"The document is licensed for a different user account"

Original message:

"Dokument ist für ein anderes Benutzerkonto lizenziert"

But I do only have that one account...?!

Maybe someone has an idea what I can do.

Thank you!

Best wishes,

Olaf