No, but could you feed the website with mismatched tags through something like tidy first? That error looks like maybe it's expecting xhtml and getting html. Maybe the site is declaring one, then using the other. Lots of software won't care because it's a pretty common error, but some panics.

HTML 5 in actual production use is only partially convertible (it's lossy). You need to get handsy with it. *

But one way around: get a markdown editor that can convert copy&paste from the web (i know of typora, it fetches (and opt. saves) images too) and then pandoc that.

* div#main, a.h1, div with naked text, i've seen things...

I recently learned about abogen and audiblez and what I want to do is blog to adiobook but I'm still stuck in getting the book from the blog.

I'm now thinking maybe c/linux would have been a better place to ask since I'm not trying to program anything. Let me know if I should move it there.