Hosted MQTT Extractor — SessionTakenOver on all topic filters, no config change on our side

Hello everyone ! 

Since this morning (3AM Paris time ) we encounter serious problem with our MQTT hosted extractor.

Setup

- CDF region: West Europe 1
- 1 Source (Azure Event Grid MQTT broker, port 8883, TLS cert auth) controlled externally
- 1 Destination (single sink, single CDF session)
- 2 Jobs (topic filters), both using the same source and same destination:
  - xxxx/OUT/xxxxxxx/AA/#
  - xxxx/OUT/xxxxxxx/BB/#

Problem

Since this morning (~03:00 UTC+1), both topic filters are stuck in connection_error with the following error looping in the event log:

Could not establish connection: Mqtt state: Server sent disconnect with reason 'None' and code 'SessionTakenOver'

Both jobs were running fine until today. No configuration changes were made on our side.

What we tried

1. Paused one job to isolate — the other still fails alone
2. Paused both, waited 10 minutes, resumed — connects briefly then gets kicked again
3. Deleted 10 legacy/unused sinks and 1 old paused job (cleanup) — no change
4. Checked Azure Event Grid status page — no incidents

Questions

1. One connection or one per job? Does the hosted MQTT extractor open a single MQTT connection per source (with multiple subscriptions), or does it open a separate connection per job? If separate connections, how are MQTT client IDs differentiated?

2. Orphaned sessions after sink/job deletion? We deleted 10 unused sinks and 1 job shortly before the issue started. Could those deletions have left orphaned MQTT sessions that are still trying to reconnect to the broker and competing for the same client ID?

3. Any platform changes? Was there any update to the hosted MQTT extractor service around 2026-04-29 ~03:00 that could have changed connection behavior?

4. How to force a clean reconnect? Is there a way to fully terminate all MQTT sessions tied to a source and start fresh, beyond pausing/resuming jobs?

 

If anyone encountered the same issue or can help on this matter this would be greatly appreciated.

Have a good one.