Google Search Console "Couldn't Fetch" ?

Anyone knows what this means or has/had the same issue?
It's a regular 2 month old whitehat blog with around 60 posts, everything was going well, already started to rank for some search terms..
Then all of a sudden all search terms were gone, and when I tried to find the problem I see Search Console "Couldn't fetch" my sitemap.

The occurrence of couldn't fetch sitemap error is usually due to a bug in Google search console. There is no easy fix for this. In reality, the status is pending and you will have to wait a few moments for the result to come back. Maybe changing your IP address or browser could fix sitemap status couldn't fetch error.

Can you access the sitemaps if you paste the urls in the address bar?
Did you check your robots.txt or .htaccess to make sure the sitemaps are accessible to crawlers?