This error can be found in the edge gateway's log file.

Problem: The edge gateway is unable to connect to your broker, because the connection attempt is interrupted.

1. Double check the instructions in the article Datalogging to MQTT broker. Do not skip this step, because the instructions may contain the solution to your problem. Some examples:
   • Unencrypted connections are NOT supported. The default port for unencrypted MQTT connections is 1883.
   • An encrypted connection is required. The default port for encrypted MQTTS connections is 8883.
   • A certificate is required for encrypted connections. Make sure that your MQTT broker has a valid CA certificate.
   • With Azure IoT Hub, Azure Event Grid, and AWS IoT Core, the MQTT Client ID (sometimes called Device ID) in the MQTT broker needs to be equal to the Edge Gateway's public ID. You can find the Edge Gateway's public ID in the URL by going to the device in the IXON Cloud Fleet Manager. For example: portal.ixon.cloud/fleet-manager/device-configurator/mxLCEyXfR5Lx/....
   • When selecting the MQTT broker and client at your data source: Don't see your MQTT broker and client? Go to Admin > MQTT and make sure that a client is added to your MQTT broker. A client is required.
   • Some MQTT broker providers require data to be sent to a specific topic. If you're unsure, please consult the service provider's documentation.
   • If you're running the MQTT broker locally, either in the edge gateway's WAN or LAN network, and at Admin > MQTT you have entered the hostname of your MQTT broker, you'll need to also add Forward DNS or disable DNS rebind protection. This is not required if you enter the IP address of your MQTT broker.
2. Test if your MQTT broker is accessible and working.
   • There are numerous public MQTT client applications available for testing. For example MQTTX or MQTT Explorer. Have a look under "Tools and Applications" at mqtt.org/software for a complete list.
3. Make sure that the edge gateway is allowed to access your MQTT broker.
   • A local company firewall may be blocking communication to your MQTT broker. If you're unsure, try to access your MQTT broker while your computer is connected to the same network as the IXON edge gateway.
4. Unsure what the status is of the MQTT connection?
   • In your MQTT broker (environment) you should be able to see if there is an active MQTT connection and also if data is being received.

Problem: The data at your MQTT broker is not up to date. It seems that the most recent data is missing and that new data is coming in slower than configured.

Cause: When an edge gateway is offline, no new data can be sent to your MQTT broker, but it will continue logging data locally. Once the connection is restored, the edge gateway will send the data to your MQTT broker. Oldest data first.

If the edge gateway is unable to clear it's local data, it'll start sending multiple data points per message in an attempt to catch up. Ultimately, it's still possible that new data is coming in faster than can be sent to your MQTT broker, meaning it simply can't catch up. This effect increases the more tags you have configured.

Solution: There are several solutions:

1. Reduce the logging interval configured at the tags of your data source, in the Fleet Manager.
2. Change the message format of your MQTT broker from JSON to Sparkplug B, in Admin > MQTT. To apply this change to your edge gateway, reboot the device (either locally or remotely in the IXON Cloud) or push a configuration to the device (if available).
   1. This will reduce the message size and will cause the locally stored data to be sent faster in most cases.
   2. Make sure that your MQTT broker can handle messages in Sparkplug B format. More information about this message format can be found in the MQTT broker article.

Keep in mind that each message may contain more than one data point when you are processing the incoming messages.

Problem: The timestamps of the data is inaccurate. It's offset by multiple seconds or minutes. This time drift also increases over time.

Cause: Timekeeping on edge devices naturally drifts over time. Timestamp correction of logged data occurs when the data is stored in IXON Cloud. This means that timestamps sent to your MQTT broker are not corrected.

Solution: You can solve this by applying time correction, either on the MQTT broker by using a message processing script or middleware to intercept messages and append timestamps, or adjust the timestamps later during post-processing. This can be done by comparing the sent time of the MQTT message to the time on the MQTT broker and applying the time difference to the timestamps of the data.