Message shortcut showing error slack api

Hello Everyone,
I am using a slack api when I trigger the message shortcut and it sends payload to postman newman webhook.
but when I trigger it , it shows me an error message in slack “Sorry! that didn’t work try again”, But newman webhook works completely fine and run the collection properly.
I want to know how to fix this error message?

Code for getting payload from slack
var previousRequest = JSON.parse(globals.previousRequest),
webhookRequestData =;
const payload = JSON.parse(webhookRequestData.payload);

Screenshot from 2021-01-21 19-49-58
Thank You