Mosquitto Denies Connection Requests following complete Backup Restore

[andrewk123]

The problem

I've been testing backup recovery due to the changes in 2025.1.

I have seen an Issue with Mosquito rejecting repeated requests following a full recovery from backup. I have tested this 3 times using 2025.1 and got the same result each time using both Rpi 4 and Generic X86_64 platforms. I have also tested it again this morning with a Rpi4 and Core 2025.2.0b7, Supervisor 2025.01.2 and Mosquito 6.5.0 (same result).

Following backup recovery, Mosquito rejects incoming connect requests (with auth failures). This does not recover on it's own (I let it run for 30 mins on one occasion. External MQTT devices as well as MQTT Explorer show the same failure (see log entries below).

Restarting Mosquito resolves the issue and following that everything recovers correctly on subsequent restarts or system shutdown/reboots.

What version of Home Assistant Core has the issue?

2025.1/2025.2.0b7

What was the last working version of Home Assistant Core?

No response

What type of installation are you running?

Home Assistant OS

Integration causing the issue

No response

Link to integration documentation on our website

No response

Diagnostics information

No response

Example YAML snippet

Anything in the logs that might be useful for us?

2025-02-03 09:43:59: New connection from 192.168.47.60:54815 on port 1883.
2025-02-03 09:43:59: Client akGarage5 disconnected, not authorised.
2025-02-03 09:44:07: New connection from 172.30.32.1:47488 on port 1883.
2025-02-03 09:44:07: Client mqtt-explorer-0d0dd6c2 disconnected, not authorised.

Additional information

No response

[MartinHjelmare]

Is Mosquito run by an add-on that is part of the backup and restore?

[andrewk123]

Yes. The Mosquitto configuration is loaded correctly as part of the restore however it (Mosquitto) rejects all connection attempts until it has been restarted once after the restore. After that all is fine. See the image below.