Hi Sreenu,
Thank you for the update. I see that you have a couple concerns. Below you will find my answers.
1. GetCampaigns.php searchStream issue.
Because this issue looks to be a concern with the client library, could you please post this concern
here so that our PHP Client library support team can assist you with this query?
2. Authentication Error.
Could you please verify your credentials by using the
OAuth doctor? This tool will help you determine if your OAuth2 credentials are configured correctly, and if they are ready to make API calls. It will also guide you through fixing any OAuth2 problems it detects and verify the corrected configuration. Please give this a try and let us know if you have any issues.