Hi, your sitemaps appear blanc when viewed in a browser but they are not blanc for search engines. This happens because the stylesheet that is needed to display XML source code in a human readable layout, is (in your case, probably after setting up a CDN in one of the performance plugins) hosted on another domain that the sitemap itself. This causes the browser to ignore the stylesheet, leaving a blanc result.
You can do two things:
1. leave it as it is, the search engines do not care about the stylesheet and will read your sitemaps just fine, or…
2. try to find a way for the CDN to not be applied to the sitemap stylesheet.
For the last option, it depends on the possibilities in your CDN plugin. If there is an option to exclude certain file types, then try adding both .xml and .xsl file types there.
