I’ve seen this happening before for large websites, apparently the Google PageSpeed Insights rendering times out for some large websites with many assets (>200). But talented I am, I’ve managed to break it with my tiny 600kB blog with 17 resources. After reaching around 60% on load/analyze, I got the the not-so-helpful message:
An error occurred while fetching or analyzing the page
Eventually found the solution, which was rather unexpected.
Tagged with error google pagespeed insights svg