JWT app returns "invalid token"

I’m having a similar issue to zoomtestjww. I have downloaded and unzipped the SDK Demo. Opened the “2017” solution in VisualStudio 2019. Then removed the references to the two missing files as described here: Can't get Zoom SDK Demo working with VS 2017 or 2019. The solution successfully builds and runs (using “Release” configuration with x86 platform). A window requesting a domain is displayed upon launch. I’ve tried different domains, including our corporate domain, the default zoom.us, as well as others. The next window appears after submitting the domain requesting “SDK JWT Token”. I’ve then retrieved the JWT token from my Zoom app (and followed the recommendations in https://marketplace.zoom.us/docs/guides/auth/jwt). However I always receive the same error described by zoomtestjww:
Error Type: LastErrorType_Auth
Error Code: 10124
Error Description:

Our account number is: 422053

Thank you.