[book_reader]

I've got a few epubs that I'm trying to convert to mobi using Calibre (I've got the latest version installed). Calibre reports the conversion succeeded and I'm able to view the converted book in Calibre using the viewer. However when I try to load/view the book using the kindle app on the ipad, it doesnt recognize the book.

Some stuff I've tried:
- I've tried submitting the mobi file to amazon via email for automated conversion but I get an automated email saying there was an error converting the file.
- I've tried generating the mobi using the old, both and the new options in the drop-down, no luck with any of those.
- I've also successfully converted another epub to mobi and am able to load/view it on my Kindle app so I doubt its a corruption in my environment or that I'm following the wrong steps.


Could this be a bug in Calibre?

Update: I also tried to open the mobi in Kindle Previewer on my PC. Its able to render the mobi when I select the device as anything except 'Kindle for ios'. When I try to select 'kindle for ios', I randomly hit one of the 3 cases below:
1. The Kindle for ios option is usually greyed out so I cant select it at all.
2. Or, sometimes I see an error saying there was an error previewing for ios.
3. Yet some other times, I see a message 'Converting to azt' followed by the error: "phantomjs_mobi82html.exe has stopped working".

I havent been yet able to figure out when/what steps will reproduce which of the 3 steps above.