On this link you can see the sitemap: http://bit.ly/2XC9J5G.
I don't understand what the error is.
From the search console I have the following indication: "The XML Sitemap cannot be analyzed because it contains one or more prefixes of the unassociated namespace. For example, the error is generated when xhtml:linknot preceded by xmlns:xhtml="http://www.w3.org/1999/xhtml" is detected in a Sitemap.
Will you help me, please solve?
Thank you very much.</xhtml:link>
Massimiliano