Home Assistant becomes unreachable randomly

Setup

  • Running on Intel NUC PC
  • Installed Home Assistant OS directly via Ubuntu
  • OS Version 16.2
  • Core Version 2025.10.3
  • Server is connected via Ethernet to a router that I am using as a network extender. This router is connected via eithernet to my Verizon FiOS router

Description

Hi everyone, for the past two-three weeks, I’ve been running into a recurring issue with my Home Assistant server. It seems like randomly (sometimes multiple times a day, sometimes once every day or two) the Home Assistant becomes unreachable locally.

When I try to connect with IPADDR:8123 from my other devices, sometimes it shows an error message saying that it the page can’t be reached.

When this spontaneous crash happens, I can hear my NUC running but when I try to connect it to my monitor via HDMI, nothing appears on the screen.

It had been working fine for the past 2 months. It’s only recently that things started behaving strangely. I have even tried a clean install and I am still seeing the issue happening sometimes.

I am trying to figure out the cause of the issue. It’s been bugging me for the past 2 weeks. I am aware that I will need to provide more info (logs and such) and that it will take a while to diagnose the issue and I am hoping for some guidance from you all on how to figure this out. Hopefully it’ll be a good learning experience. But since this issue isn’t replicable on demand, this will probably be an ongoing thread where I try to provide more info on each subsequent crash.

Logs

Here is a snippet of Host logs from before I noticed it crashed. I rebooted it by turning the power off and on at approximately 13:41

2025-10-21 13:19:00.301 homeassistant systemd[1]: Started libcontainer container 533ca05aa1bd2bbce5504a55c8b351e06eac0c932c98d5994cd2627afc4f8735.
2025-10-21 13:19:04.359 homeassistant systemd[1]: NetworkManager-dispatcher.service: Deactivated successfully.
2025-10-21 13:19:07.013 homeassistant systemd[1]: var-lib-docker-overlay2-d4efed4f064e3434e26b647e52d10f5256ed15678144b9169711da0f7313c59e\x2dinit-merged.mount: Deactivated successfully.
2025-10-21 13:19:07.014 homeassistant systemd[1]: mnt-data-docker-overlay2-d4efed4f064e3434e26b647e52d10f5256ed15678144b9169711da0f7313c59e\x2dinit-merged.mount: Deactivated successfully.
2025-10-21 13:19:07.081 homeassistant systemd[1]: Started libcontainer container dda9c8507b764ebcb74ae32ab79f36bdb601c0eae0c82f9039b9d4615dcb3831.
2025-10-21 13:19:10.419 homeassistant systemd[1]: var-lib-docker-overlay2-88d757d6a793636cb793739819886cc81af9302645315ca8b0d7f804db366392\x2dinit-merged.mount: Deactivated successfully.
2025-10-21 13:19:10.419 homeassistant systemd[1]: mnt-data-docker-overlay2-88d757d6a793636cb793739819886cc81af9302645315ca8b0d7f804db366392\x2dinit-merged.mount: Deactivated successfully.
2025-10-21 13:19:10.504 homeassistant systemd[1]: Started libcontainer container e35e68ddd6baec464f5fa8d7483030acf96fd18f55c1304b3da92d60e0be622a.
2025-10-21 13:19:10.530 homeassistant kernel: hassio: port 7(vethc0f8c63) entered blocking state
2025-10-21 13:19:10.530 homeassistant kernel: hassio: port 7(vethc0f8c63) entered disabled state
2025-10-21 13:19:10.530 homeassistant kernel: vethc0f8c63: entered allmulticast mode
2025-10-21 13:19:10.530 homeassistant kernel: vethc0f8c63: entered promiscuous mode
2025-10-21 13:19:10.531 homeassistant NetworkManager[455]: <info>  [1761052750.5311] manager: (vethc0f8c63): new Veth device (/org/freedesktop/NetworkManager/Devices/14)
2025-10-21 13:19:10.560 homeassistant kernel: eth0: renamed from vethb8df9c4
2025-10-21 13:19:10.561 homeassistant NetworkManager[455]: <info>  [1761052750.5613] device (vethc0f8c63): carrier: link connected
2025-10-21 13:19:10.561 homeassistant dockerd[564]: time="2025-10-21T09:19:10.561336309-04:00" level=info msg="Skipping check for route to send NA, EMSGSIZE" eid=5de98f09a8420e9fee0aa7bbc6c08a7b3b2abe355c97ad6bbbbf0fe57ce2c88b ep=addon_45df7312_zigbee2mqtt net=hassio nid=fdecf0bb137b14e0ec185a4c82d6fcd4cdaed66ce53b8295eb982811cb264b69
2025-10-21 13:19:10.561 homeassistant kernel: hassio: port 7(vethc0f8c63) entered blocking state
2025-10-21 13:19:10.561 homeassistant kernel: hassio: port 7(vethc0f8c63) entered forwarding state
2025-10-21 13:19:11.219 homeassistant kernel: warning: `matter-server' uses wireless extensions which will stop working for Wi-Fi 7 hardware; use nl80211
2025-10-21 13:19:45.676 homeassistant systemd[1]: systemd-hostnamed.service: Deactivated successfully.
2025-10-21 13:19:45.677 homeassistant systemd[1]: systemd-timedated.service: Deactivated successfully.
2025-10-21 13:41:55.983 homeassistant kernel: Linux version 6.12.43-haos (builder@75f99402e96f) (x86_64-buildroot-linux-gnu-gcc.br_real (Buildroot -g49cc2691) 13.4.0, GNU ld (GNU Binutils) 2.43.1) #1 SMP PREEMPT_DYNAMIC Mon Sep  8 17:12:31 UTC 2025
2025-10-21 13:41:55.983 homeassistant kernel: Command line: BOOT_IMAGE=(hd0,gpt2)/bzImage root=PARTUUID=8d3d53e3-6d49-4c38-8349-aff6859e82fd rootwait zram.enabled=1 zram.num_devices=3 systemd.machine_id=fe70375c92bc401ab300f7e96acb7b61 fsck.repair=yes console=tty0 rauc.slot=A
2025-10-21 13:41:55.983 homeassistant kernel: BIOS-provided physical RAM map:

Logs from Core

s6-rc: info: service legacy-services: starting
services-up: info: copying legacy longrun home-assistant (no readiness notification)
s6-rc: info: service legacy-services successfully started
2025-10-21 09:00:36.824 WARNING (Recorder) [homeassistant.components.recorder.util] The system could not validate that the sqlite3 database at //config/home-assistant_v2.db was shutdown cleanly
2025-10-21 09:00:36.843 WARNING (Recorder) [homeassistant.components.recorder.util] Ended unfinished session (id=31 from 2025-10-21 12:53:37.114280)
s6-rc: info: service s6rc-oneshot-runner: starting
s6-rc: info: service s6rc-oneshot-runner successfully started
s6-rc: info: service fix-attrs: starting
s6-rc: info: service fix-attrs successfully started
s6-rc: info: service legacy-cont-init: starting
s6-rc: info: service legacy-cont-init successfully started
s6-rc: info: service legacy-services: starting
services-up: info: copying legacy longrun home-assistant (no readiness notification)
s6-rc: info: service legacy-services successfully started
2025-10-21 09:09:15.198 WARNING (Recorder) [homeassistant.components.recorder.util] The system could not validate that the sqlite3 database at //config/home-assistant_v2.db was shutdown cleanly
2025-10-21 09:09:15.216 WARNING (Recorder) [homeassistant.components.recorder.util] Ended unfinished session (id=32 from 2025-10-21 13:00:36.816571)
s6-rc: info: service s6rc-oneshot-runner: starting
s6-rc: info: service s6rc-oneshot-runner successfully started
s6-rc: info: service fix-attrs: starting
s6-rc: info: service fix-attrs successfully started
s6-rc: info: service legacy-cont-init: starting
s6-rc: info: service legacy-cont-init successfully started
s6-rc: info: service legacy-services: starting
services-up: info: copying legacy longrun home-assistant (no readiness notification)
s6-rc: info: service legacy-services successfully started
2025-10-21 09:19:03.544 WARNING (Recorder) [homeassistant.components.recorder.util] The system could not validate that the sqlite3 database at //config/home-assistant_v2.db was shutdown cleanly
2025-10-21 09:19:03.581 WARNING (Recorder) [homeassistant.components.recorder.util] Ended unfinished session (id=33 from 2025-10-21 13:09:15.190151)
s6-rc: info: service s6rc-oneshot-runner: starting
s6-rc: info: service s6rc-oneshot-runner successfully started
s6-rc: info: service fix-attrs: starting
s6-rc: info: service fix-attrs successfully started
s6-rc: info: service legacy-cont-init: starting
s6-rc: info: service legacy-cont-init successfully started
s6-rc: info: service legacy-services: starting
services-up: info: copying legacy longrun home-assistant (no readiness notification)
s6-rc: info: service legacy-services successfully started
2025-10-21 09:42:22.377 WARNING (Recorder) [homeassistant.components.recorder.util] The system could not validate that the sqlite3 database at //config/home-assistant_v2.db was shutdown cleanly

Supervisor logs. Here I noticed that there was a DNS server error. Maybe this could be it?

2025-10-21 09:19:10.371 INFO (MainThread) [supervisor.homeassistant.core] Detect a running Home Assistant instance
2025-10-21 09:19:10.371 INFO (MainThread) [supervisor.addons.manager] Phase 'application' starting 1 add-ons
2025-10-21 09:19:10.391 INFO (SyncWorker_7) [supervisor.docker.manager] Cleaning addon_45df7312_zigbee2mqtt application
2025-10-21 09:19:10.617 INFO (MainThread) [supervisor.docker.addon] Starting Docker add-on ghcr.io/zigbee2mqtt/zigbee2mqtt-amd64 with version 2.6.2-1
2025-10-21 09:19:10.816 INFO (MainThread) [supervisor.api.middleware.security] /supervisor/info access from 45df7312_zigbee2mqtt
2025-10-21 09:19:13.798 INFO (MainThread) [supervisor.auth] Auth request from 'core_mosquitto' for 'mqtt-user'
2025-10-21 09:19:14.060 INFO (MainThread) [supervisor.auth] Successful login for 'mqtt-user'
2025-10-21 09:19:15.634 INFO (MainThread) [supervisor.misc.tasks] All core tasks are scheduled
2025-10-21 09:19:15.635 INFO (MainThread) [supervisor.host.info] Updating local host information
2025-10-21 09:19:15.636 INFO (MainThread) [supervisor.resolution.check] Starting system checks with state running
2025-10-21 09:19:15.636 INFO (MainThread) [supervisor.resolution.checks.base] Run check for free_space/system
2025-10-21 09:19:15.639 INFO (MainThread) [supervisor.resolution.checks.base] Run check for ipv4_connection_problem/system
2025-10-21 09:19:15.639 INFO (MainThread) [supervisor.resolution.checks.base] Run check for no_current_backup/system
2025-10-21 09:19:15.639 INFO (MainThread) [supervisor.resolution.module] Create new suggestion create_full_backup - system / None
2025-10-21 09:19:15.639 INFO (MainThread) [supervisor.resolution.module] Create new issue no_current_backup - system / None
2025-10-21 09:19:15.639 INFO (MainThread) [supervisor.resolution.checks.base] Run check for docker_config/system
2025-10-21 09:19:15.640 INFO (MainThread) [supervisor.resolution.checks.base] Run check for trust/supervisor
2025-10-21 09:19:15.644 INFO (MainThread) [supervisor.core] Supervisor is up and running
2025-10-21 09:19:15.648 INFO (MainThread) [__main__] Running Supervisor
2025-10-21 09:19:15.648 INFO (MainThread) [supervisor.resolution.checks.base] Run check for dns_server_ipv6_error/dns_server
2025-10-21 09:19:15.663 INFO (MainThread) [supervisor.host.services] Updating service information
2025-10-21 09:19:15.667 INFO (MainThread) [supervisor.host.network] Updating local network information
2025-10-21 09:19:15.669 INFO (MainThread) [supervisor.resolution.checks.base] Run check for dns_server_failed/dns_server
2025-10-21 09:19:15.683 INFO (MainThread) [supervisor.resolution.checks.base] Run check for pwned/addon
2025-10-21 09:19:15.684 INFO (MainThread) [supervisor.resolution.checks.base] Run check for disabled_data_disk/system
2025-10-21 09:19:15.684 INFO (MainThread) [supervisor.resolution.checks.base] Run check for security/core
2025-10-21 09:19:15.684 INFO (MainThread) [supervisor.resolution.checks.base] Run check for disk_lifetime/system
2025-10-21 09:19:15.686 INFO (MainThread) [supervisor.resolution.checks.base] Run check for multiple_data_disks/system
2025-10-21 09:19:15.686 INFO (MainThread) [supervisor.resolution.check] System checks complete
2025-10-21 09:19:15.687 INFO (MainThread) [supervisor.resolution.evaluate] Starting system evaluation with state running
2025-10-21 09:19:15.805 INFO (MainThread) [supervisor.host.sound] Updating PulseAudio information
2025-10-21 09:19:15.814 INFO (MainThread) [supervisor.host.manager] Host information reload completed
2025-10-21 09:19:15.880 INFO (MainThread) [supervisor.resolution.evaluate] System evaluation complete
2025-10-21 09:19:15.880 INFO (MainThread) [supervisor.resolution.fixup] Starting system autofix at state running
2025-10-21 09:19:15.881 INFO (MainThread) [supervisor.resolution.fixup] System autofix complete

Next Steps

I just found out about the Home Assistant Observer so during the next crash, I will be trying to access that link to see what I can figure out from there.

What else should I take note of when I notice the next crash? And what can I do to further investigate right now?

Just as bad a using a wireless connection.

However as you have observed that HA has blackscreened with a connected monitor it is unlikely to be just network issues. Likewise DNS issues will not cause HA to crash completely.

Check the config/home-assistant.log1 file as this is the log from before the crash.

Check the memory and cpu use using the system monitor integration. These should not climb continuously.

Try starting in safe mode. If that does not crash then a 3rd party integration is at fault.