The azure search service will start throttling your search requests when it’s being overloaded and it’s running out of resources. Blue Matador automatically watches the percentage of throttled requests and creates events when the number is high.
When the number and/or complexity of search queries exceeds the resources allocated to your search service, search queries and index requests will start to get throttled. This will result in the service responding with HTTP statuses of 429 or 503.
You should configure your client to retry failed requests. If you are seeing sustained throttling, you should consider: