[Home](./index.md) > [@snowplow/react-native-tracker](./react-native-tracker.md) > [EmitterConfigurationBase](./react-native-tracker.emitterconfigurationbase.md) > [onRequestFailure](./react-native-tracker.emitterconfigurationbase.onrequestfailure.md) ## EmitterConfigurationBase.onRequestFailure property A callback function to be executed whenever a request fails to be sent to the collector. This is the inverse of the onRequestSuccess callback, so any non 2xx status code will trigger this callback. Signature: ```typescript onRequestFailure?: (data: RequestFailure, response?: Response) => void; ```