A. Verify the AWS IoT Device Shadow service is subscribed to the appropriate topic and is executing the AWS Lambda function.
B. Verify that AWS IoT monitoring shows that the appropriate AWS IoT rules are being executed, and that the AWS IoT rules are enabled with the correct rule actions. Most Voted
C. Check the AWS IoT Fleet indexing service and verify that the thing group has the appropriate IAM role to update DynamoDB.
D. Verify that AWS IoT things are using MQTT instead of MQTT over WebSocket, then check that the provisioning has the appropriate policy attached.