This issue has been resolved:
If anyone else is here with the same issue it may be that you’re using the Master account endpoints unnecessarily. These endpoints have the additional string /accounts/{accountId}
in the URLs and will yield errors if are not calling the endpoints from an enabled Master account with sub-account relationships:
Please use the non-Master account endpoints. In this instance, for example:
USE Zoom Phone API
DO NOT USE Zoom Phone Master API