Whats the importance of redirect URLand Postback URL while APP creation

[Pradeep_Jaiswar]

Unable to generate access token

Generating an auth code and generating accessing tokens using the auth code is a three-step process. The first two steps must be completed in a web browser: Perform Authentication: Access detailed instructions at Perform Authentication . Receive Auth Code: For this step, visit Receive Auth Code . Generate Access Token: Finally, to generate the access token, refer to Generate Access Token . You will receive the auth code on the Redirect URL URL in the second step, which needs to be used to gen…

Additionally, updates to orders are sent to a postback URL. It is optional to provide a postback URL when you create an app.

I hope the above information is useful.