Follow the order above. Most access issues are caused by mismatched product protocol, device credentials, topic format, or network reachability.
Check Item Expected Result Product status Product has been released. Protocol The protocol matches the actual device access method. Device type Direct, gateway, sub-device, or video type is selected correctly. Thing model Property, function, and event identifiers match the payload. Tenant visibility The current user can access this product.
Check Item Expected Result Device number Same as the username/client identifier required by the protocol. Device secret Same as the password or signature secret. Device status Device is not disabled or deleted. Product binding Device belongs to the expected product. Gateway relation Sub-device is bound to the correct gateway when needed.
Check broker address, port, firewall, container mapping, TLS setting, and proxy configuration. When using EMQX or FMQ, also check listener status and authentication plug-in logs.
Symptom Common Cause Device connects but no data Topic is wrong, payload is not JSON, or identifier does not match the thing model. Data appears in broker but not platform Rule, consumer, or protocol parser did not process the message. Command is not received Device did not subscribe to the command topic or is offline. Value is ignored Data type, unit, enum value, or timestamp format is invalid.
Location Purpose Device logs Confirm connection, subscription, and publish behavior. Broker logs Confirm authentication, ACL, and topic delivery. Backend logs Confirm protocol parsing and business processing. Platform device log Confirm whether FastBee received and stored the message.
