Could you please show me the real layout of the data and the URL you contact and the method you use?
Of course you can elide your real ID and actual repo path, and please don’t post your access token in any format, but I’d like to see it laid out as a URL since that is what I’ll use to reproduce. Here’s an example that works (if you fill in real details). I assert that it matches the article well enough, but more usefully & how I got it so fast: it also matches “what our UI does” as our best API advice described in this article.
That’s for using the installation_id mentioned in sub-point 2; using deploy keys is a pain in the butt since you have to get them into GitHub so we recommend what is now default on our service and has been for almost 2 years - using the GitHub app.
Anyway, hopefully that pattern and my description of how I got it will help you out with your own call, but if not, please give me the data in that format to help troubleshoot!