Thank you for your message.
So yes, that is because this specific endpoint is not publicly available, you would need to contact us in case you need it so we can set up your account. It should be written in the endpoint documentation as a warning.
Anyway you are in the right place, let’s continue in private message here to make sure this endpoint is what you are looking for and choose the correct parameters for your needs.
I’m working at Deliver.ee, we have already been using this endpoint in production for years now (so we might already have contacted you), I have to modify our lib because of the sandbox url change, and I need to pass our test suite. But now I get this error message for one of my test. I’ve tried your postman collection and your online documentation, same result. So why?