iot-hub-include-last-known-errors.md

title	include file
description	include file
author	SoniaLopezBravo
ms.service	azure-iot-hub
services	iot-hub
ms.topic	error-reference
ms.date	04/22/2019
ms.author	sonialopez
ms.custom	include file

Get Endpoint Health in the REST API gives the health status of the endpoints and the last known error, to identify the reason an endpoint isn't healthy. This table lists the most common errors.

Last Known Error	Description/when it occurs	Possible Mitigation
Transient	A transient error occurred and IoT Hub will retry the operation.	Observe routes resource logs.
InternalError	An error occurred while delivering a message to an endpoint.	This error is an internal exception but also observe the routes resource logs.
Unauthorized	IoT Hub isn't authorized to send messages to the specified endpoint.	Validate that the connection string is up to date for the endpoint. If it changed, consider an update on your IoT Hub. If the endpoint uses managed identity, check that the IoT Hub principal has the required permissions on the target.
Throttled	IoT Hub is being throttled while writing messages into the endpoint.	Review the throttle limits for the affected endpoint. Modify configurations for the endpoint to scale up if needed.
Timeout	Operation timeout.	Retry the operation.
Not Found	Target resource doesn't exist.	Ensure that the target resource exists.
Container Not Found	Storage container doesn't exist.	Ensure the storage container exists.
Container disabled	Storage container is disabled.	Ensure the storage container is enabled.
MaxMessageSizeExceeded	Message routing has a message size limit of 256 Kb. The message size being routed exceeded this limit.	Check if message size can be reduced by using fewer application properties or fewer message enrichments.
PartitioningAndDuplicateDetectionNotSupported	Service bus might not have duplicate detection enabled.	Disable duplicate detection from Service Bus or consider using an entity without duplicate detection.
SessionfulEntityNotSupported	Service bus might not have sessions enabled.	Disable session from Service Bus or consider using an entity without sessions.
NoMatchingSubscriptionsForMessage	There's no subscription to write message on the service bus topic.	Create a subscription for IoT Hub messages to be routed to.
EndpointExternallyDisabled	Endpoint isn't in an active state so IoT Hub can send messages to it.	Enable the endpoint to bring it back to active state.
DeviceMaximumQueueDepthExceeded	Service bus size limit has been reached.	Consider removing messages from the target Event Hubs to allow new messages to be ingested into the Event Hubs.