No OpenGraph preview image or description when sharing Glitch site on Facebook

All you see is this generic preview when you share the link in Facebook:

The Facebook sharing debugger gives the error “Curl error: 18 (PARTIAL_FILE)”:

See Sharing Debugger - Facebook for Developers

I’m testing with an unmodified copy of the “glitch-hello-website”.

This was acknowledged by someone from Glitch support back in Oct 2019, but it seems it hasn’t been fixed yet.

Please could you guys fix this.