@Kenneth Cheung The 403 Forbidden error indicates that the server understood the request, but is refusing to authorize it. This error can occur for a variety of reasons, such as invalid credentials or insufficient permissions.
To troubleshoot this issue, please make sure that you have provided the correct API key in the request headers. You can obtain the API key from the Azure portal by navigating to your search service and selecting "Keys" under "Settings". Also, ensure that the API key is valid and has not expired.
If the API key is correct and valid, please check if you have the necessary permissions to perform the operation. You can refer to the "Permissions required for REST APIs" section in the following document for more information: https://docs.microsoft.com/en-us/azure/search/search-security-api-keys#permissions-required-for-rest-apis
If you are still facing issues, please let me know and provide me with more details about your API request.