Failed to import epub ebook. error included

hey everyone. I have an ebook I bought from a Norwegian bookstore. I was able to upload it to readlang with no problems, but when I tried to import it here I get this error:
Importing failed - NoneType’ object has no attribute ‘content’

Do you all know what this means + what the fix is? It’s in epub format.

Can you please send us the file to support(at)lingq.com and we will look into it for you. Sounds like file format is broken.

done, thanks!