Epub file didn't created

[minekasetsu]

I tried to convert the Dawn Traveler from Gila Translation Monster and Gaia Chronicles Blog with the image from it as the cover image , and the programs seems to be working normally, except that the epub file isn't there when it done.

After I check it, I found that the problem seems to be the cover image, and when I use image from novelupdates instead for the cover image, no problem happened.

Hope this will help.