# MQTT Transmission Connection Error

**URL:** <https://forum.inductiveautomation.com/t/mqtt-transmission-connection-error/112891>\
**Category:** Ignition\
**Created:** [December 18, 2025, 12:40pm UTC](https://forum.inductiveautomation.com/t/mqtt-transmission-connection-error/112891 "2025-12-18T12:40:59Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![danig](https://avatars.discourse-cdn.com/v4/letter/d/e19adc/32.png) [@danig](https://forum.inductiveautomation.com/u/danig)\
**Post date:** [December 18, 2025, 12:40pm UTC](https://forum.inductiveautomation.com/t/mqtt-transmission-connection-error/112891/1 "2025-12-18T12:40:59Z")

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MQTT Transmission Connection Error

We are using the MQTT Transmission module version 5.00 on an Ignition Edge gateway.  
The connection between the Edge station and the Ignition server (version 8.3) is implemented through a one-way data diode.

When the data diode experiences a power failure, the MQTT Transmission connection to the server is lost. After the data diode is powered back on, the MQTT Transmission module shows that it is reconnected; however, no new data is transmitted. The Ignition server continues to display only the last known tag values.

Data transmission resumes only after manually triggering  
**Transmission Control → Refresh** , which forces a refresh.

We would like to know how to configure the system so that communication and data transfer recover automatically after a data diode outage, without requiring manual intervention.

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**Author:** ![Nol](https://avatars.discourse-cdn.com/v4/letter/n/8e8cbc/32.png) [@Nol](https://forum.inductiveautomation.com/u/Nol)\
**Post date:** [December 18, 2025, 7:19pm UTC](https://forum.inductiveautomation.com/t/mqtt-transmission-connection-error/112891/2 "2025-12-18T19:19:08Z")

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8.1 so might be a bit different but MQTT Transmission -\> Settings -\> Sets -\> Your Server Set -\> Advanced then do you have this off since it defaults to false?

```python
Auto-reconnect RPC Client If checked, the RPC client will automatically reconnect to the server. If not checked, it will try to reconnect at publish time.
(default: false)

```

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<div class="post-metadata">

**Author:** ![danig](https://avatars.discourse-cdn.com/v4/letter/d/e19adc/32.png) [@danig](https://forum.inductiveautomation.com/u/danig)\
**Post date:** [December 21, 2025, 7:35am UTC](https://forum.inductiveautomation.com/t/mqtt-transmission-connection-error/112891/3 "2025-12-21T07:35:27Z")

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> [@Nol](#):
>
> `Auto-reconnect RPC Client	`

Thank you, we will try the auto-reconnect RPC client.

We also considered using a script that checks the MQTT Transmission connection status and refreshes the tags if needed. However, we cannot find any built-in Transmission status tag (for example, a Connected/Disconnected tag).

Is there a specific tag or mechanism we should monitor to determine the MQTT Transmission connection status?  
If not, what is the recommended best practice for detecting a lost Transmission connection (e.g., heartbeat tag, Engine-side monitoring, or another approach)?

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<div class="post-metadata">

**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [December 21, 2025, 2:31pm UTC](https://forum.inductiveautomation.com/t/mqtt-transmission-connection-error/112891/4 "2025-12-21T14:31:57Z")

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Sounds like a flaw in the data diode. The transmission module cannot receive any status from the broker backwards through the diode.