Register the Mediaflow application

Under Name, enter Mediaflow.
Under Supported account types, keep Single tenant only.
Under Redirect URI, choose the platform Web and enter Mediaflow's redirect URI exactly as written: https://api.mediaflow.com/1/oauth2/verify
Select Register.

The Register an application page with the name Mediaflow, Single tenant only, the Web platform with Mediaflow's redirect URI, and the Register button highlighted.