I just got the Kobo 3 weeks ago.
Yes, I've tried the other configurations - same problem.
"Alley Oop through the Ulysses Trees". I got it from Smashwords, but I see Kobo also has it via Smashwords. All my other books are generic, from Gutenberg, Creative Commons, Smashwords, etc.
I see someone with a Kindle is having a similar problem. I didn't have a cover on the Kobo until yesterday. So in my case, it isn't a cover.
https://www.mobileread.com/forums/sho...d.php?t=256573
The only other purchase came from O'Reilly and it's a PDF.
"Illustrated Guide to Astronomical Wonders" I wanted the finderscope charts on my tablet. I did check it out on the Kobo - it loaded and could be read.