OAuth 2.0 set up - Invalid Redirect URL (4,700)

Setting new App Oauth 2.0 results in Error

While creating a new app / oauth 2 authentication I am getting persistent exception - Invalid Redirect URL (4,700) even though URL seems to be valid. I tried to use recommended for Postman URL described here - Guide: Making a Zoom API Call with OAuth Credentials in Postman - to no avail

Invalid Redirect URL (4,700) .

Hi, can you please confirm having white listed the URLs before starting the auth process?

What would be the course of actions to whitelist a URL?