This is my sitemap, it starts like this:
<?xml version="1.0" encoding="UTF-8"?>
<urlset
xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
xmlns:xhtml="http://www.w3.org/1999/xhtml/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9
http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">
<!-- Domain Name Policy (DNP) in: https://github.com/jfoclpf/autocosts/wiki/Domain-name-policy -->
<url>
<loc>https://autocostos.info/AR</loc>
<changefreq>weekly</changefreq>
<xhtml:link rel="alternate" hreflang="x-default"
href="https://autocosts.info/" />
<xhtml:link rel="alternate" hreflang="es-AR"
href="https://autocostos.info/AR" />
<xhtml:link rel="alternate" hreflang="en-AU"
href="https://autocosts.info/AU" />
<xhtml:link rel="alternate" hreflang="es-BO"
href="https://autocostos.info/BO" />
<xhtml:link rel="alternate" hreflang="pt-BR"
href="https://autocustos.info/BR" />
<xhtml:link rel="alternate" hreflang="en-CA"
href="https://autocosts.info/CA" />
<xhtml:link rel="alternate" hreflang="es-CL"
href="https://autocostos.info/CL" />
<xhtml:link rel="alternate" hreflang="zh-CN"
href="https://autocosts.info/CN" />
<xhtml:link rel="alternate" hreflang="es-CO"
href="https://autocostos.info/CO" />
<xhtml:link rel="alternate" hreflang="es-CR"
href="https://autocostos.info/CR" />
But Google Search console insists that
Your Sitemap or Sitemap index file does not properly declare the namespace
They just give an example on line 16: Line 16 Parent tag: url Tag: link
Line 16 corresponds to <xhtml:link rel="alternate" hreflang="x-default" href="https://autocosts.info/" />
What am I doing wrong?