Follow
The process here was:
1. Replicate the issue. I had enough information in the bug report to do that no problem. This was definitely a real problem.
2. Check the logs. The issue was there in the logs complete with a not working link to API documentation for the upstream provider.
3. Find the real URL for the documentation that I needed to confirm that indeed what has been working just fine for years is indeed still documented as should be working. No changes there.
4. Find the problem in my own code. It's been a while since I touched this, but at the same time I only needed to look in 2 fairly small source files and while some might be horrified that I chose C++ for this, it was an easy read. Good job, past me.
5. Found where I was doing a thing that could throw an exception and replaced the calls to that with a new function that wraps that in a try and does something reasonable on a caught exception.
6. Test that it's working again.