Cannot transfer ebooks to Kobo despite my PC and Kobo being authorised to the same account

This has been driving me nuts! I used to be able to transfer books - usually from local library - but now despite the same authorisation for both devices I am using it will not open them once I have dragged and dropped them to my Kobo. Actually, I've just re checked and now it won't even allow me to drag and drop. I get that no entry sign.

SUSISUNG@GMAIL.COM | Adobe ID (urn:uuid:33512e00-2787-4c3b-9a95-285785ef7f16) thats for the Kobo

SUSISUNG@GMAIL.COM | Adobe ID (urn:uuid:33512e00-2787-4c3b-9a95-285785ef7f16) and that's for my PC

Looks the same to me!

Can anyone help? I downloaded the lastest version. 

Thanks - hopefully!