Unable to connect to Dynamics 365 - 401 unauthorized error


We have recently done the internet-facing deployment on our dynamics 365 version. We were trying to connect to Dynamics using the OOB web API (REST end point), but we were not able to connect. We get 401 access denied even after we provided all accurate parameters to postman get a token wizard. We verified that everything is accurate from our end & assuming that it’s an issue with the postman tool. Any help?


Can you attach some screenshots and a link to the official documentation?