I have a ZD421. I see my device in my account so it is correctly registered.
I have tested the SendFileToPrinter endpoint from your testing service (https://developer.zebra.com/apis/sendfiletoprinter-model#/SendFileToPrinter/SendFiletoPrinter) using the “Production server and it returns me a SUCCESS response.
However, it does not print the file that I send.
What is the issue here ?