I got an error with the sitemap option in this plugin, but I don't think the plugin is the problem.
Everytime I test the sitemap_index.xml on Google, I get a 403 html error.
I tried google xml sitemap, strictly sitemap, disabling plugins, modify htaccess, ecc... but nothing works.
Can you give me the solution to this problem? I wasted over a week to resolve this.
The sitemap is here: