Are you referring to this tutorial?
I just used this, and it is working, able to submit to Google sheets.
Yes, this tutorial. It worked wonderfully on my previous 2 games, but not on this current game I'm building, which is weird.
The only difference is that for this current game:
1) I'm sending over more parameters than the previous (working) games
2) I also do another AJAX call to load a local JSON file for this current game
Sorry if my description is rather vague, not really well-versed in coding :(