what if AWS_IOT_MQTT_CLIENT_ID is not unique

mqtt client id should be unique under your amazon IoT account

aws_iot_config.h

#define AWS_IOT_MQTT_CLIENT_ID "MyDock123 - updater" ///< MQTT client ID should be unique for every device

but Amazon document didn’t mention what will happen if not unique

here is my test:

the previous connected one will be kicked offline when next one connect

WARN: disconnectCallbackHandler L#70 MQTT Disconnect
Auto Reconnect is enabled, Reconnecting attempt will start now
ERROR: main L#264 An error occurred in the loop :-12.

For Mass Production

using mac address as unique ID maybe a good idea