We have set up credentials in the sandbox to get a token, We prefer to test with Postman. We are receiving the error "OAU-222 Account does not exist". We verified the authorization header is correctly set to Basic + base64_encoded( Client ID + ":" + Client Secret ).
We saw another post indicating Authorization and Content-type should be passed in the body of the post, not as headers. When we tried that we got a different error. Any help woudl be greatly appreciated. We downloaded the sample Postman collection, but it seems to be out of date and does not match the JWT Authorization Code Flow as described in the documentation.