You work for a logistics service provider which operates hundreds of trucks. Most of the trucks are equipped with several sensors for tracking the routes, monitoring the temperature of the shipments, monitoring speed etc. You have built an IoT solution which organizes all the end devices into a centralized system, making use of IoT Central as the central management platform. On the IoT Central dashboard you notice that not all the data from your device TempSensor1004 reaches the cloud. You start debugging on the device and you repetitively receive error code 429. 
What action should you take?

Answer options:

A.Raise a ticket for the customer support
B.Reduce the send frequency of messages
C.Check if the device has the right credentials
D.Check if the body of the requests is of valid format

Correct Answer: B
Option A is incorrect because this type of error doesn’t necessitate calling the customer support.
Option B is CORRECT because error code 429 shows that the device is affected by throttling, and that’s why some messages don’t arrive. Try decreasing the frequency of the send operation under the throttling thresholds.
Option C is incorrect because in case of authentication issues, error code 401 is thrown.
Option D is incorrect because it is the error code 400 that indicates validation or parsing problems.
References: 

https://docs.microsoft.com/en-us/azure/iot-central/core/troubleshoot-connection
https://docs.microsoft.com/en-us/azure/iot-central/core/quick-monitor-devices
https://docs.microsoft.com/en-us/azure/azure-resource-manager/management/azure-subscription-service-limits#iot-hub-device-provisioning-service-limits