Hi @Rahul kumar ,
Thank you for providing the details. I apologize for the delay in my response and any inconvenience this may have caused.
On the basis of the above provided details we are suspecting that Client ID and Client Secret may causing the issue to resolve that in the google console you have to configure the OAuth and after configuring that you will be getting the Client ID and Client Secret so paste those details in the required path.
So, to configure OAuth and get the Client ID and Client Secret below is the document for your reference we request you to proceed accordingly and share your concerns if you have any.
https://learn.microsoft.com/en-us/connectors/gmail/#creating-an-oauth-client-application-in-google
Thankyou.