ZHA “send queue full / max limit” now daily after channel change (only restart clears)

Configuration Zigbee
1

Setup

Hardware: Home Assistant Green + USB Zigbee coordinator (ZHA only; no Matter/Thread)

Devices: Philips Hue bulbs (paired to ZHA) + Qaroora no-neutral Zigbee wall switches

Channel: moved from 11 → 20

USB 3.0 mitigation: long extension to keep the dongle away from HA Green/other cables

Exact error (from Logs)

Error during service call to light.turn_on: Failed to send request:
Failed to enqueue message: <sl_Status.ZIGBEE_MAX_MESSAGE_LIMIT_REACHED: 3075>

(Also happens on scene.turn_on. Logger: homeassistant.components.websocket_api.http.connection, Source: components/websocket_api/commands.py:317.)

Symptoms

I used to get this occasionally on channel 11.

Since switching to 20, it’s daily. In the morning I find the error; a restart fixes it temporarily, but it returns even with zero usage while I’m away.

Tried

Rejoined devices after channel change.

Moved coordinator away from USB 3.0 noise via long cable.

Only a full restart clears it.

Ask

  1. Is channel 20 prone to Wi-Fi overlap—should I try 15 or 25?

  2. Any known issues with no-neutral switches flooding the network/queue?

  3. What ZHA debug logs/diagnostics should I capture to identify the culprit?

Happy to provide exact coordinator model/firmware, ZHA diagnostics, network map, and Wi-Fi channel details. Thanks!

2

Hello Abdullah ,

This includes the interference chart I believe.

3

Good idea to check channel usage before you do anything. If you download diagnostics (in the overflow menu on the ZHA integration card), towards the end of the file you get should be something like this:

    "energy_scan": {
      "11": 2.509919386096536,
      "12": 4.69985354430736,
      "13": 2.509919386096536,
      "14": 0.6967547825628676,
      "15": 87.33047519856483,
      "16": 0.9017765778954641,
      "17": 4.15070068297423,
      "18": 3.2311094587038967,
      "19": 7.659755505061292,
      "20": 88.70042934643088,
      "21": 93.76433891498253,
      "22": 93.76433891498253,
      "23": 78.25348754651363,
      "24": 6.789392891308996,
      "25": 2.509919386096536,
      "26": 91.05606689948522
    },

The numbers represent the amount of noise on each channel, including Zigbee and wi-fi. In this example channels 15 and 20 are pretty busy (Zigbee is actually on 15 and working well) while 25 is relatively clear.

Your error may be caused by interference, but it may also be that too many commands are being triggered at once, flooding the network. This sometimes happens when you send a lot of commands to Zigbee groups in an automation.