Datasource down or faulted

Symptom

One of two things:

• Enable fails. Toggling Enable on an input datasource row bounces back to Disabled and shows an error code such as model_not_paired or adapter_connect_failed.
• A running source faults mid-stream. A previously-streaming datasource stops producing predictions; the row shows a fault indicator and a red banner appears. Under the hood the runtime dropped to a faulted, then idle, state.

Note

Enabling a datasource does not start streaming. It prepares the runtime (loads the model, connects the adapter). You press Start to begin inference. A row that is Enabled but not predicting is often just waiting for Start — that is by design.

Confirm

Identify which stage failed.

• Read the error code on the row. The code names the failed step directly:

  • model_not_paired → the datasource has no model assigned.
  • adapter_connect_failed → the protocol connection (OPC-UA handshake / MQTT broker connect / Modbus probe) failed — almost always a network or endpoint problem.

• Check the backend log for the connect attempt and fault reason:

  docker compose -f docker-compose.release.yml logs backend | grep -iE "datasource|adapter|fault|enable"

• A mid-stream fault comes from a read error on the live source (a tag stopped responding). When that happens the runtime tears down to a clean idle state: the model is unloaded and the adapter is unbound. Recovery is not automatic — the source must be re-enabled from scratch.

Fix

1. model_not_paired — assign a model to the datasource first, then Enable again. A datasource must be paired with a model before it can run.

2. adapter_connect_failed — the runtime could not reach the source. The Enable already rolled the row back to Disabled cleanly, so fix the connection and retry:

   • Verify the endpoint address, port, and credentials in the datasource config.
   • Confirm the box has network reachability to the OPC-UA server / MQTT broker / device.
   • For a CSV source, confirm the file path and that the file is present and readable.
   • Use the form’s Test Connection against the current values, then Enable again.

3. A source that faulted mid-stream has been torn down to idle — the model was unloaded and the adapter unbound. Re-establish it fully:

   • Fix the underlying source problem (reconnect the sensor / restore the tag / fix the network).
   • Enable the datasource again (this reloads the model and reconnects the adapter).
   • Press Start to resume streaming.

Caution

Only one input datasource can be Enabled at a time. Enabling source B automatically disables source A. If a source you expected to be running shows Disabled, check whether enabling a different source switched it off.

Prevent

• Pair the model and map all channels before going live. Most Enable failures are pre-flight validation: a missing model pairing or an incomplete tag-to-channel mapping (gaps or over-fills). Complete these once and Enable succeeds first try.
• Stabilise the source before Start. A flaky OPC-UA endpoint or intermittent broker will fault the stream and force a full re-enable. Confirm a stable connection with Test Connection before pressing Start.
• Expect the two-step flow. Enable prepares; Start streams. Building this into the operating procedure avoids “it’s enabled but nothing’s happening” tickets.

Related

• Connecting Datasources — adapter types, connection config, tag mapping.
• Your First Inference — model load and run flow.