My sitemap get's rejected

Are there any new solutions for this problem? I have been trying for weeks to resolve this issue but I really cannot find what’s wrong.
The site’s url is :
The source code is : GitHub - Thanasis-Traitsis/Photographers-Website

My xml file seems to be fine. I run all the tests and I build it with the help of the netlify’s plugin. But I still get the error “sitemap.xml couldn’t fetch”.

Thank you in advance for your help.

Take a look at:

Thanks for the answer. I will try to make contact with google then.