E_Adept_NO_Fullfilment_Result Pocketbook Ereader

I want to download newly bought ebooks to my Pocketbook ereader.  But then when I want to download the transferred books to my ereader I get this error:   E_Adept_NO_Fullfilment_Result 

I have already contacted the service from which I bought the ebook, contacted adobe (they can't help as ADE is a free service) etc... so I have been told to come to this community for help with this issue. 

How can I bypass this error and download the ebook I bought?

If the error means that the book has been downloaded on another account before (maybe this happened by mistake as I tried to connect to my devices) how can I delete from other accounts so this isn't an issue anymore?

hope someone can help, have spent many hours trying to resolve this issue to no avail.