Hi Sumit, thank you for your interest in the add-on.
The error messaging here is a little misleading - this actually indicates that the initial token request using your client credentials is not returning successfully.
If you have access to utility like Postman, you can test your request and credentials by making a request to the Oauth endpoint specified here: https://community.sailpoint.com/t5/IdentityNow-Wiki/IdentityNow-REST-APIs/ta-p/80132 - this should allow you to see what the error message being returned is, and to understand why the initial request is failing.
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