MTN momoapi Authentication

Hi, i am using postman to test the MTN momoapi and when i make a post request using ‘requesttopay’ i get 401 unauthorised error.

Are you using a subscription key?

https://momodeveloper.mtn.com/api-documentation/api-description/

Yes, i used a subscription key and it does not work as it should.

Would you mind sending a screenshot of the request you have in Postman?