The external API endpoint returned a 4xx or 5xx HTTP status code. The API gateway (AWS API Gateway, Azure API Management) rejected the request due to throttling or auth failure. The response payload from the remote service did not match the expected JSON array format Snowflake requires. The external function's MAX_BATCH_ROWS setting sends too many rows, exceeding the API payload size limit

Step 1: Run the external function with a single test row and inspect the error details in the Snowflake query history.. Step 2: Check the API gateway logs for the actual HTTP response code and body returned to Snowflake.. Step 3: Verify the remote service is healthy and the API endpoint URL has not changed.. Step 4: Confirm the Snowflake API integration IAM role or Entra app still has permission to invoke the API gateway.. Step 5: Reduce MAX_BATCH_ROWS on the external function if payload size is causing gateway rejections.

High severityexecution

Power BI Refresh Error:
002140

What does this error mean?

Snowflake received an error response from the external API endpoint when invoking an external function, often because the remote service returned a non-200 HTTP status or an unexpected payload format.

Common causes

1The external API endpoint returned a 4xx or 5xx HTTP status code
2The API gateway (AWS API Gateway, Azure API Management) rejected the request due to throttling or auth failure
3The response payload from the remote service did not match the expected JSON array format Snowflake requires
4The external function's MAX_BATCH_ROWS setting sends too many rows, exceeding the API payload size limit

How to fix it

1Step 1: Run the external function with a single test row and inspect the error details in the Snowflake query history.
2Step 2: Check the API gateway logs for the actual HTTP response code and body returned to Snowflake.
3Step 3: Verify the remote service is healthy and the API endpoint URL has not changed.
4Step 4: Confirm the Snowflake API integration IAM role or Entra app still has permission to invoke the API gateway.
5Step 5: Reduce MAX_BATCH_ROWS on the external function if payload size is causing gateway rejections.

Frequently asked questions

What HTTP response format does Snowflake expect from an external function?

Snowflake expects a JSON object with a 'data' key containing an array of [row_number, result] pairs — for example: {"data": [[0, "result1"], [1, "result2"]]}.

Can I test an external function before deploying it in production?

Yes — use a development Snowflake account or a separate external function pointing to a test API endpoint. You can also call the function directly with SELECT my_ext_function(test_value) and inspect the output.