Help Center> IoT Device Access> FAQs> Device Integration> Why Was the Error Code 4 Returned When I Used the IoT Device SDK for C for Device Connection?
Why Was the Error Code 4 Returned When I Used the IoT Device SDK for C for Device Connection?
It is because the entered account name or password was incorrect. For details about the error codes returned upon connection failures, see the error code description in the MQTTAsyn.h file.
Parent topic: Device Integration
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