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Seeing this messages indicates a problem with the MQTT client implementation.
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Statement
Client ID: abc, IP:x.x.x.x was disconnected. reason: Sent second CONNECT message.Client ID: abc, IP:x.x.x.x disconnected ungracefully.
Meaning
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This disconnect reason implies a protocol violation by the client |
When you see this message, the client got disconnected by the broker because it sent a second CONNECT packet on an already existing MQTT connection.
See MQTT specification.
After a Network Connection is established by a Client to a Server, the first Packet sent from the Client to the Server MUST be a CONNECT Packet [MQTT-3.1.0-1].
A Client can only send the CONNECT Packet once over a Network Connection. The Server MUST process a second CONNECT Packet sent from a Client as a protocol violation and disconnect the Client [MQTT-3.1.0-2]. See section 4.8 for information about handling errors.
Seeing this messages indicates a problem with the MQTT client implementation.
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