ebook won't open on ereader even after reauthorizing both ADE and ereader

I tried the solution referenced here - https://community.adobe.com/t5/digital-editions-discussions/ereader-not-authorized-to-open-this-book/m-p/9489945#M52484 but it didn't work or I didn't understand it properly.

I borrowed and then downloaded a book from the library, it opens in ADE, I transfer to my device in ADE, I disconnect my device and after it finishes fulfilling I try to open it - error that it's not authorised.

I have reauthorized both ADE and my device, downloaded the books again, multiple times.

This started happening in January and I haven't been able to use my ereader since.

Help!