Using the Store API how do I Submit an In App Product?

Question

I used the instructions found here:
https://learn.microsoft.com/en-us/windows/uwp/monetize/csharp-code-examples-for-the-windows-store-submission-api

To create an IAP using the API in C#. It successfully creates the IAP but it won't submit. Initially I got a:

---> System.Exception: { "statusCode": 429, "message": "Rate limit is exceeded. Try again in 290 seconds." }  

This was with creating one IAP. So I slowed down the code by putting 30 seconds in between each step and a 5 minute wait before submitting. This allowed me to successfully submit the IAP Submission, but I then received the error:

Submission has failed. Please check the Errors collection of the submissionResource response.  

When I investigate it with a debugger I see the error that I have this message:

Submission has active validation errors which cannot be exposed via API, please visit https://developer.microsoft.com to see the issue.  

Has anyone been successful in submitting an IAP Submission using the Store API? Help?