Hello @Priya Jha ,
Thanks for the question and using MS Q&A platform.
As per the error message - it's clearly says credentials is incorrect or do not have the permission to access.
Make sure you have met the prerequisites and required permissions on the Google Cloud Storage account as mentioned in this document: Copy data from Google Cloud Storage using Azure Data Factory or Synapse Analytics.
And also, you can checkout this video on Copy data from GCP into Azure.
Hope this will helps. Please let us know if any further queries.