Troubleshooting

Start Here: Symptom Triage

Use this table to jump to the first checks quickly.

Need definitions for licensing/scheduler terms? See the Glossary.

Symptom	First check	WebUI location	Next section
Cannot access WebUI	`systemctl status lqosd`	N/A (UI unavailable)	No WebUI at x.x.x.x:9123
Traffic is not shaping	verify `to_internet` / `to_network`, service state	WebUI Dashboard	LibreQoS Is Running, But Traffic Not Shaping
Scheduler appears unhealthy	check `lqosd` and `lqos_scheduler` logs	WebUI -> Scheduler Status	Scheduler status in WebUI looks unhealthy
Topology/flow views blank	confirm recent traffic and `lqosd` health	WebUI -> Flow Globe / Tree / ASN Analysis	Flow Globe / Tree Overview / ASN Analysis appears blank
Urgent issue code appears	open issue details and map code	WebUI -> Urgent Issues	Urgent issue codes and first actions
Mapped circuit cap events	validate license state and mapped counts	Insight UI + WebUI -> Urgent Issues	Mapped circuit limit reached

Common Issues

Where in WebUI

Service/health overview: WebUI -> Dashboard
Scheduler readiness: WebUI -> Scheduler Status
High-priority alerts: WebUI -> Urgent Issues
Topology/traffic visualization: WebUI -> Network Tree Overview and Flow Globe
Shaped records review: WebUI -> Shaped Devices Editor

Before asking in chat: collect this evidence

Collect these first to reduce back-and-forth:

sudo systemctl status lqosd lqos_scheduler
journalctl -u lqosd --since "30 minutes ago"
journalctl -u lqos_scheduler --since "30 minutes ago"

If integration-related, also include:

ls -lh /opt/libreqos/src/network.json /opt/libreqos/src/ShapedDevices.csv

And include:

current version/build
integration type and strategy (if used)
exact symptom and when it started

User password not working

Current builds will:

migrate older auth files automatically
redirect /login.html to /first-run.html when no users exist

If the correct username/password still fails, first restart lqosd and try again:

sudo systemctl restart lqosd

Only remove lqusers.toml if you are intentionally resetting access or if the file is corrupt and cannot be repaired. After removing it, restart lqosd and open BOX_IP:9123/login.html; the WebUI should redirect you to first-run setup automatically.

No WebUI at x.x.x.x:9123

The WebUI is controlled by the lqosd service. In current builds, most WebUI access failures are caused by lqosd not being healthy.

Start by checking:

sudo systemctl status lqosd

Then follow the full workflow in Service lqosd is not running or failed to start below.

LibreQoS Is Running, But Traffic Not Shaping

In /etc/lqos.conf, ensure that to_internet and to_network are set correctly. If not, simply swap the interfaces between those and restart lqosd and the scheduler.

sudo systemctl restart lqosd lqos_scheduler

Make sure your services are running properly

sudo systemctl status lqosd lqos_scheduler

The service lqos_scheduler is dependent on the lqosd service being in a healthy, running state.

On-a-stick shaping looks wrong or one direction is weak

On-a-stick mode depends on queue splitting per direction. If TX queue discovery is wrong or override_available_queues is mis-set, directional mapping can be degraded.

Check:

sudo systemctl status lqosd
journalctl -u lqosd --since "10 minutes ago"

Then verify queue-related config in /etc/lqos.conf and restart:

sudo systemctl restart lqosd lqos_scheduler

Service lqosd is not running or failed to start

Check to see the state of the lqosd service:

sudo systemctl status lqosd

If the status is ‘failed’, examine why using journalctl, which shows the full status of the service:

journalctl -u lqosd --since "10 minutes ago"

Press the End key on the keyboard to take you to the bottom of the log to see the latest updates to that log.

Lqosd will provide specific reasons it failed, such as an interface not being up, an interface lacking multi-queue, or other concerns.

Advanced lqosd debug

At the command-line, run:

sudo RUST_LOG=info /opt/libreqos/src/bin/lqosd

which runs lqosd in debug mode, and will provide specifics regarding why it failed to start.

Service lqos_scheduler shows errors

If sudo systemctl status lqosd lqos_scheduler reveals that the lqos_scheduler service has issues, you can export a comprehensive log of the errors to a file:

sudo journalctl -u lqos_scheduler --since "1 day ago" --no-pager > lqos_sched_log.txt

This exports a log file to lqos_sched_log.txt. You can review this file to see what caused the scheduler to error out.

If the scheduler fails immediately after a restart with a message like Socket (typically /run/lqos/bus) not found, that indicates lqosd had not finished binding the local bus yet. Current builds wait briefly for bus readiness at scheduler startup instead of crashing immediately, so repeated startup panics after restart should no longer be expected.

If an integration subprocess fails, current builds keep the scheduler alive, publish a shortened output preview to the scheduler status/error surfaces, and save the full captured output to a timestamped file under /tmp such as lqos_scheduler_uisp_integration_YYYYMMDD_HHMMSS.log.

Scheduler status in WebUI looks unhealthy

Recent builds expose scheduler readiness/state in the WebUI (Node Manager).

If scheduler status appears down/stale:

Verify both services:

sudo systemctl status lqosd lqos_scheduler

Check recent scheduler logs:

journalctl -u lqos_scheduler --since "30 minutes ago"

Check lqosd bus/log state for scheduler-ready or scheduler-error messages:

journalctl -u lqosd --since "30 minutes ago"

If config/integration changes were recent, restart services cleanly:

sudo systemctl restart lqosd lqos_scheduler

If status repeatedly oscillates between ready/error, collect both logs and confirm integration credentials/timeouts in /etc/lqos.conf.

RTNETLINK answers: Invalid argument

This tends to show up when the MQ qdisc cannot be added correctly to the NIC interface. This would suggest the NIC has insufficient RX/TX queues. Please make sure you are using the recommended NICs.

Python ModuleNotFoundError in Ubuntu 24.04

pip uninstall binpacking --break-system-packages --yes
sudo pip uninstall binpacking --break-system-packages --yes
sudo pip install binpacking --break-system-packages
pip uninstall apscheduler --break-system-packages --yes
sudo pip uninstall apscheduler --break-system-packages --yes
sudo pip install apscheduler --break-system-packages
pip uninstall deepdiff --break-system-packages --yes
sudo pip uninstall deepdiff --break-system-packages --yes
sudo pip install deepdiff --break-system-packages

All customer IPs are listed under Unknown IPs, rather than Shaped Devices in GUI

cd /opt/libreqos/src
sudo systemctl stop lqos_scheduler
sudo python3 LibreQoS.py

The console output from running LibreQoS.py directly provides more specific errors regarding issues with ShapedDevices.csv and network.json Once you have identified the error and fixed ShapedDevices.csv and/or Network.json, please then run

sudo systemctl start lqos_scheduler

Flow Globe / Tree Overview / ASN Analysis appears blank

Some views require enough recent data to render meaningfully. If pages look empty:

Confirm lqosd is healthy.
Wait for traffic/data to accumulate.
Reload the page after 1-2 minutes.
Check logs for websocket or ticker warnings:

journalctl -u lqosd --since "10 minutes ago"

If still blank under normal traffic, collect recent logs and open an issue.

Site Map appears blank or slow

Site Map has one extra dependency beyond normal WebUI data feeds: current builds fetch bbox/bootstrap data and raster tiles from https://insight.libreqos.com.

If Site Map alone is blank or slow:

Confirm lqosd is healthy.
Confirm the box can reach insight.libreqos.com from its management network.
Wait briefly and reload the page; the browser retries tile requests automatically while cold tiles are being populated upstream.
Check recent lqosd logs:

journalctl -u lqosd --since "10 minutes ago"

If the rest of WebUI is healthy but Site Map continues to fail, treat it as a map/tile dependency issue rather than a general scheduler or shaping failure.

Virtual node promotion collision (network.json)

If LibreQoS.py fails with an error like Virtual node promotion collision: 'AP_A' already exists at this level., you have a "virtual": true node whose children get promoted into a parent level where a node with the same name already exists.

Rename one of the colliding nodes (names must be unique among siblings after virtual-node promotion), or restructure the hierarchy so promoted children won’t collide. For a visual of the logical-to-physical promotion flow and CPU placement, see Advanced Configuration Reference.

Mapped circuit limit reached

If logs mention messages like:

Mapped circuit limit reached
Bakery mapped circuit cap enforced

ShapedDevices.csv can contain unlimited entries, but without a valid Insight subscription/license LibreQoS admits only the first 1000 valid mapped circuits into active shaping state.

The default 1000 mapped-circuit limit applies when Insight is:

missing
expired
otherwise invalid
operating with offline-invalid local grant state

Typical operator-visible symptoms:

prominent mapped-circuit-limit warning in WebUI
left-hand navigation usage indicator showing approach to or exhaustion of the 1000 limit
journalctl -u lqosd messages showing requested/allowed/dropped mapped counts
partial shaping, with circuits beyond the active limit left outside shaping state

Recommended checks:

Confirm Insight/license status in the UI.
Review lqosd logs for requested/allowed/dropped counts.
Reduce mapped circuit count (short term) or update licensing/limits (long term).

Urgent issue codes and first actions

WebUI urgent issues include machine-readable codes. Use them to triage quickly.

Code	Meaning	First checks	Typical fix path
`MAPPED_CIRCUIT_LIMIT`	Bakery is enforcing a mapped-circuit limit.	Insight license status, `journalctl -u lqosd` for requested/allowed/dropped counts.	Reduce mapped circuits immediately or update license/limits.
`TC_U16_OVERFLOW`	Queue/class minor IDs exceeded the Linux tc u16 range on a CPU queue.	`journalctl -u lqos_scheduler -u lqosd`, topology depth/queue distribution.	Increase queue count and/or simplify/rebalance hierarchy (for example with integration strategy or root promotion changes).
`TC_QDISC_CAPACITY`	Planned auto-allocated qdiscs exceed the per-interface safe budget or Bakery’s conservative memory-safety preflight before apply.	Estimated per-interface qdisc counts, qdisc-kind breakdown, and memory fields in the urgent issue context, `journalctl -u lqos_scheduler -u lqosd`, `on_a_stick` and `queue_mode` config.	Reduce the planned qdisc load for this run (for example fewer circuits/devices in the test shape) before retrying; do not trust partial apply.
`BAKERY_MEMORY_GUARD`	A chunked Bakery full reload was stopped mid-apply because available host memory fell below the safety floor.	`journalctl -u lqosd`, available/total memory in the urgent issue context, and recent Bakery apply progress.	Treat the run as failed, reduce memory pressure or queue footprint, and retry only after the host is stable.
`XDP_IP_MAPPING_CAPACITY`	Required IP mappings exceed the current XDP kernel map capacity.	`ShapedDevices.csv` row shape, IPv4/IPv6 mix, one-device-vs-many-device assumptions, `journalctl -u lqos_scheduler -u lqosd`.	Reduce required mappings immediately (for example fewer devices or IPv4-only test shape), or raise kernel map capacity in a coordinated change.
`XDP_IP_MAPPING_APPLY_FAILED`	One or more IP mapping inserts failed during apply.	`journalctl -u lqos_scheduler -u lqosd` for summarized failure examples and counts.	Fix the underlying mapping failure, then rerun; do not trust partial shaping.

Operational pattern:

Open urgent issue details in WebUI (code/message/context).
Pull matching logs from lqosd and lqos_scheduler.
Apply the immediate mitigation.
Acknowledge/clear the issue in UI once stable.