Hi Pablo,

refer to this FAQ for common troubleshooting: http://storejextensions.org/faq/my-images-sitemap-doesn-t-embed-all-images-in-my-site-what-could-be-the-problem.html

Take care that this website works normally for images: https://www.navisyachts.com/index.php?option=com_jmap&format=images&xslt=1

I have no clue of the exact issues because it may depend on many factors listed in the FAQ.
I suggest to leave all filters empty and contact the hosting provider to ensure that loopback connections are allowed.

After that use the precaching to ensure to crawl all the links in the sitemap.

PS: If you need on site support for all your domains you have to get multiple licenses.

John