Troubleshooting

I cannot receive any data on my subscriber and the TwinCAT Error List shows multiple errors that say “Invalid minor version received”.

This error is usually thrown whenever the source data has changed, e.g. when additional fields have been added to a publisher data set. In this case, the version information inside of the OPC UA Pub/Sub paket is incremented and it is therefore required to make the new configuration known to the subscriber.

The easiest way to do that is to export the updated publisher configuration into a configuration file and import it on the subscriber.

A connection to the message broker can not be established and the TwinCAT Error List shows multiple errors that say “Error connecting MQTT client MQTT_ERR_NOT_FOUND”.

Please make sure that you have used the correct hostname or IP address of your MQTT message broker.

A connection to the message broker can not be established and the TwinCAT Error List shows multiple errors that say “Error connecting MQTT client MQTT_ERR_CONN_TIMEDOUT”.

Please make sure that you have used the correct hostname or IP address of your MQTT message broker and that the broker can be reached at that address. Also make sure that you have specified the correct TCP/IP port of your message broker, e.g. 1883 or 8883.

A connection to the message broker can not be established and the TwinCAT Error List shows multiple errors that say “Error connecting MQTT client MQTT_ERR_TLS_VERIFY_FAIL”.

This error message is usually thrown when the Pub/Sub driver does not accept the message broker certificate, which is typically related to using a wrong CA certificate.

Please make sure that you have specified the correct CA certificate.

A connection to the message broker can not be established and the TwinCAT Error List shows multiple errors that say “Error connecting MQTT client MQTT_ERR_TLS_HANDSHAKE_FAIL”.

This error message is usually thrown when the message broker does not accept your client certificate. It may also be thrown if you have specified no client certificate at all.

Please make sure that you have specified the correct client certificate and that it is trusted by the message broker.

A connection to the message broker can not be established and the TwinCAT Error List shows multiple errors that say “Error connecting MQTT client MQTT_ERR_TLS_KEY_NOTFOUND”.

This error message is usually thrown when the client key cannot be found.

Please make sure that the client key exists under the path that you specified in the MQTT connection settings.

A connection to the message broker can not be established and the TwinCAT Error List shows multiple errors that say “Error connecting MQTT client MQTT_ERR_TLS_KEY_INVALID”.

This error message is usually thrown when the client key cannot be opened.

Please make sure that you have specified a valid client key file in the MQTT connection settings and that you haven’t mixed the client key with the client certificate.

A connection to the message broker can not be established and the TwinCAT Error List shows multiple errors that say “Error connecting MQTT client MQTT_ERR_TLS_CERT_NOTFOUND”.

This error message is usually thrown when the client certificate cannot be found.

Please make sure that the client certificate exists under the path that you specified in the MQTT connection settings.

A connection to the message broker can not be established and the TwinCAT Error List shows multiple errors that say “Error connecting MQTT client MQTT_ERR_TLS_CERT_INVALID”.

This error message is usually thrown when the client certificate cannot be opened.

Please make sure that you have specified a valid client certificate file in the MQTT connection settings and that you haven’t mixed the client certificate with the client key.