Problem importing ebook

I think the book might be too big. It’s a really long web novel. Is there a file size limit?

I think there must be a limit. I tried chopping the file up into smaller parts and eventually it was accepted. The original file was 16,163 KB and the one that finally got accepted was 1,785 KB

Audio size limit is 20MB, but there’s is no text limit and if text is too long it simple gets split into parts. 16mb file shouldn’t be size issue, I assume there’s something else wrong with it.