Opeing the source, i see the page has been "optimized" by W3 total cache. I am going to exclude it, and report here.

Actually, I don't think Total cache is guilty here. Here is the source:

 
<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="//lebearcnc.com/wp-content/plugins/wpforo/assets/css/wpforo-sitemap.xsl"?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
	<sitemap>
		<loc> https://lebearcnc.com/forums/topic-sitemap1.xml</loc> 
	</sitemap>
	<sitemap>
		<loc> https://lebearcnc.com/forums/topic-sitemap2.xml</loc> 
	</sitemap>
	<sitemap>
		<loc> https://lebearcnc.com/forums/profile-sitemap1.xml</loc> 
	</sitemap>
	<sitemap>
		<loc> https://lebearcnc.com/forums/profile-sitemap2.xml</loc> 
	</sitemap>
	<sitemap>
		<loc> https://lebearcnc.com/forums/profile-sitemap3.xml</loc> 
	</sitemap>
	<sitemap>
		<loc> https://lebearcnc.com/forums/forum-sitemap.xml</loc> 
	</sitemap>
</sitemapindex>
<!-- XML Sitemap generated by wpForo SEO -->
<!--
Performance optimized by W3 Total Cache. Learn more:  https://www.boldgrid.com/w3-total-cache/ 

Mise en cache objet de 0/74 objets utilisant redis
Mise en cache de page à l’aide de redis (Requested URI is rejected) 
Chargement lent
Mise en cache de la base de données utilisant redis  (Request-wide modification query)

Served from: lebearcnc.com @ 2023-03-31 13:34:22 by W3 Total Cache
-->

Should not this line be the first ?

<!-- XML Sitemap generated by wpForo SEO -->

If you confirm, and tell me where this is generated, I guess I can fix this.

Thnaks for your help.

Hi @le-bear,

We have checked the URL, as it is in the Screenshot you provided, and the page works.

Just note if you have done any manipulations, please bring them back to default(not to get any problems).

Yes, thank you, I found the guilty plugin in between...