Thank you for your interest!
I should’ve been clearer: this application has been running for 5+ years. It uses the legacy API.
It magically fixed itself.
I considered sending logs of the issue’s irreproducibility. For example, I have a simple script that handles my customer’s vendor partner leads by generating a Keap /go/ url and redirecting. During that process, the script uses the Keap data query service. In my testing on the live site during the outage, it would work about one out of three times.
We put up with it for 24 hours until the next maintenance heartbeat.
It’s entirely possible that there was a problem with GoDaddy infrastructure. When I ran the script on my laptop and it worked 100% of the time.