Hi Akshay,
Thank you for providing the requested information.
To provide insights,
RESOURCE_NOT_FOUND error are one of the common mutate errors. The common cause is when the request attempts to mutate or otherwise reference a resource that does not exist or has been removed. Or, the given resource name for the resource is malformed. To handle this, use a search request to retrieve the resource name for an existing resource before submitting a mutate request. Review our
client library guides, which include documentation on how to construct valid resource names in every supported language. To help you address this issue, don't create resource names manually. Use one of the helper methods offered by our client libraries.
I hope it helps.
Best regards,