The book I tried to download is a PDF version that I downloaded from the internet. It is about 205 pages.
I also have troubles converting my Amazon Audibles. Only 1 out of every 5 books work.
So your digital protection error message is referring to DRM most likely.
It is already PDF. Do you mean if I solved tye DRM issue it will most likely work?
I think so. For example, I can get a book and open it as a PDF or an EPUB file. I can read these, but I can’t highlight and copy the text from that PDF or EPUB and then paste it somewhere else. The text in the DRM protected ebook PDF can only be manipulated within the app that I use to view that PDF/EPUB file. I wish that I could be more helpful, but that’s about all I know. My best guess is that if your file didn’t have DRM, the file would be like any other document on your computer and you could upload it to Lingq or copy and paste it into the lesson page.
If I buy a DRM protected book from Google Books, I can read it on any device where I am logged in on my google book app. I HAVE TO use the app
If I buy a book that isn’t DRM protected, I can read that file anywhere and send it anywhere. The file doesn’t prevent me from directly putting the file onto any device. I could email it to myself and open it on another computer instead of using my google book account.
Google usually tells you if the book is DRM protected and whether audio files can be exported to other devices. It’s rare to find things without DRM these days.
If this isn’t the issue, I’m not sure what other protection would be on the PDF. Hope this helps!