clarkwinkelmann When I read your comment, there was a light on me.
I mean manually go to the site and create a file that way FTP file to add to the site.
When you said it was a dynamic page, I knew it wasn't supposed to be, and when I deleted it and checked it again, everything was fine.
Thanks mate.
Note: accidental sitemap.I've already added xml, so this is a problem. I added it with my own hand yesterday. Turns out there wasn't supposed to be a file. (https://www.xml-sitemaps.com/)