Question about robots.txt and Sitemap.xml Why are they not being read?

Question

htaccess

Guys, hello everyone. Closer to the point: I create a sitemap of a certain resource, I try to feed it to Google, it answers with an error (empty file or file is not available) I check it in a simple old-fashioned way. I open site.ru/sitemap.xml (the engine replies that there is no such file and asks to return to the main page. Strange. Torment and again torment. Then I come across an article stating that this could all be due to CNC in the engine. Let's say. The problem is that the engine itself is commercial, purchased, the license is all business, but there is not much opportunity to dig deeper into it, since everything is encrypted there by the author. txt and specify where the sitemap is located, but this attempt also failed. txt and the file does not contain my changes! I return to the server - everything is there. Through a browser, no. How to overcome all this trouble and make the sitemap accessible? (Strongly do not kick knowledge at least)