Losing context of the Zendesk Window during OAuth due to Internal Redirection

Hi,
We are trying to do OAtuh on Zendesk using the below URL format, which we load in the new Popup window which ultimately redirects us to the Login page and we were able to do the authentication using the credentials. But during this flow, we are Loosing the context of the Original window which was opened. Because of that we are not able to read the query params from the Successful redirect URL.

Now we wanted to understand what possibly can be the issue with that?

We suspect if there is some particular header specific to security or any other issue which don't allow us to do that.
 

URL Format:
“https://ringcentraldev.zendesk.com/oauth/authorizations/new?response_type=code&redirect_uri=https%3A%2F%2Fsample-api.integration.ringcentral.com%2Fcrm-framework%2Fv1%2Fservices%2Fzendesk%2Fauth%2Fredirect&client_id=sample-idl&scope=read+tickets%3Awrite+users%3Awrite&state=%257B%2522%D”