Common API response codes and their meaning


LUIS will be retired on October 1st 2025 and starting April 1st 2023 you will not be able to create new LUIS resources. We recommend migrating your LUIS applications to conversational language understanding to benefit from continued product support and multilingual capabilities.

The authoring and endpoint APIs return HTTP response codes. While response messages include information specific to a request, the HTTP response status code is general.

Common status codes

The following table lists some of the most common HTTP response status codes for the authoring and endpoint APIs:

Code API Explanation
400 Authoring, Endpoint request's parameters are incorrect meaning the required parameters are missing, malformed, or too large
400 Authoring, Endpoint request's body is incorrect meaning the JSON is missing, malformed, or too large
401 Authoring used endpoint key, instead of authoring key
401 Authoring, Endpoint invalid, malformed, or empty key
401 Authoring, Endpoint key doesn't match region
401 Authoring you are not the owner or collaborator
401 Authoring invalid order of API calls
403 Authoring, Endpoint total monthly key quota limit exceeded
409 Endpoint application is still loading
410 Endpoint application needs to be retrained and republished
414 Endpoint query exceeds maximum character limit
429 Authoring, Endpoint Rate limit is exceeded (requests/second)

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