My website's sitemap is not getting fetched in google search console 😭

[RennyHarlin]

My blog website at https://rennyharlin.github.io has a robots.txt as well as a sitemap.xml file. But, when I upload it to google search console it says -

I've been having trouble with this for over 2 months. Please help me.
I just need to know what I'm doing wrong that is preventing my sitemap from getting recognized. Also the domain I'm using is the free one from github. Also my site repository is available at https://github.com/RennyHarlin/blog