Problem With Sitemap

google is saying the below about our sitemap, is it a cs cart or server issue?

Sitemap has errors
Sitemap is HTML
1 instance

Your Sitemap appears to be an HTML page. Please use a supported sitemap format instead.
Line: 3
Sitemap has errors
Sitemap is HTML
1 instance

Your Sitemap appears to be an HTML page. Please use a supported sitemap format instead.
Line: 3

CS-Cart offers two sitemaps - .html and .xml. You should use xml sitemap for Google. Please check the following article

https://docs.cs-cart.com/4.8.x/user_guide/addons/google_sitemap/index.html

thanks solved

CS-Cart offers two sitemaps - .html and .xml. You should use xml sitemap for Google. Please check the following article

https://docs.cs-cart.com/4.8.x/user_guide/addons/google_sitemap/index.html