"Unable to create JSON configuration file" error

URL of experiment: Pavlovia, Pavlovia

Description of the problem: v2021.2.3 is trying to kill me (/hk). I was already having an issue with Pavlovia not automatically downloading resources out of nowhere when these experiments were working fine for months and I hadn’t touched them. I made a quick fix (not an ideal workaround, but it’ll do), but now I’m getting the “403 Forbidden nginx” error page when I try to pilot the experiments. This happened to me before and I think the solution was to set it to inactive and then back to piloting/running and it worked fine. But now when I do that, I’m getting this error:

This is certainly a new one. We’ve already been collecting data for months with these experiments, so I can’t/don’t want to delete it and make a new one. Can someone please tell me what this is and how to fix it? Thank you.