There are others who can go through how it is something wrong with your files and that you need to fix them so that they are up to the standards that Kobo will accept. I personally feel that the great high definition display of the AuraHD is better used with the alternative reading programs that are now available and can be launched from the Kobo "Home Page". These other programs will likely have no problem with your files.
https://www.mobileread.com/forums/sho...67&postcount=2
Luck;
Ken