PageSpeed Insights: "Diagnose performance issues: unknown error"

[nath-artlist]

Hopefully this is the right place for PageSpeed Insights problems?

It shows "Diagnose performance issues: unknown error" for artlist.io: https://pagespeed.web.dev/report?url=https%3A%2F%2Fartlist.io%2F

I've checked:

• Server logs - we return multiple HTTP 200s to a Lighthouse UA in Google's ASN.
• Running in Chrome's dev tools - no issue.
• Running this repo - no issue.

At a loss for where else to look, any thoughts?

[connorjclark]

This looks like a problem with PSI that we should investigate - typically sites with heavy usage of WebGL (#8557) are problematic for PSI, but this site doesn't seem to use any/a lot of webgl.