AI Mesh [RT-AX59U] keeps disconnecting and slowing down

[Kujot]

Hi,

I've seen multiple questions like that, but with no successfull follow up's, always finishing on some generic hints like "restart router, check updates, etc.". 

It looks that the simple AI Mesh network consisting of two RT-AX59U routers connected via WiFi Link (ground floor with cable connection to the Internet + 1st floor device with no physicall barriers between them - located near the stairs) is continuously dropping some devices. It concerns mostly IoT devices and Android phones. On the phone there is "missing connection" issue, sometimes it's just a slow-down, or a DNS_PROBE errors. When trying to load a page it keeps hanging for like 20-30 sec, but immediately I switch off the WiFi it loads correctly. 

I tried the hints like upgrade, firmware reset, switching the 2,4 from 5G so they are broadcasted separately, but it doesn't help. 

I noticed that the issue is mostly in the connection between two Asus devices (once I click Optimize on the second of them - 1st floor) the situation get's better for some time. Issue is especially visible in the mornign - over the night devices are not used. 

Is there any way to restore normal functioning of the AI Mesh, or it's just a slogan about seamless connection? 😞 

[Aureliannn_ASUS]

Hi @Kujot ,

thank you for the detailed information.
To help us more accurately identify the cause of RT-AX59U AiMesh wireless backhaul leading to IoT / Android disconnection, delays, or DNS failures, please help confirm and provide the following:

1. Full firmware version numbers for both RT-AX59U units.
   (e.g., 3.0.0.4.xxx_xxxxx)

2. AiMesh topology details:
   • Which unit is the main router (Ground Floor)
   • Which unit is the AiMesh node (1st Floor)
   • Reported backhaul signal strength (dBm)
   • Any possible interference sources nearby (other routers, WiFi extenders)
   Even with clear line-of-sight, backhaul channel interference can still cause nighttime dropouts.

3. WiFi details when Android / IoT devices disconnect:
   • Incorrect IP assignment
   • “Connected but no Internet” status
   • DNS resolution failures

4. Please confirm if Smart Connect is enabled.

5. Please specify which band your IoT devices primarily connect to (2.4GHz or 5GHz).

6. Does the nighttime instability follow a pattern? For example:
   • Devices unreachable when you use them the next morning
   • Devices stay connected but lose IP after idle
   • Some Android phones only recover after toggling WiFi off/on

7. When the issue occurs, please submit a Feedback report via the router UI.
   If the network is down, the UI will generate an offline diagnostic data link.
   Please download the file, compress it into a ZIP, and share a cloud link for our analysis.

Additionally, please send us the following via private message:
• Product serial number (SN)
• Time the feedback report was submitted
• Email used for the report
• Time the issue occurred
• MAC address of your device
• A network architecture diagram of your current environment (a simple drawing is fine)

Thank you for your cooperation. We will proceed with further analysis once we receive the details.

[Kujot]

Thanks @Aureliannn_ASUS for a quick response and all the hints. I've shared the details in PM. Let's see if it helps to find out what could be the issue.

[kisselive]

---remove 

[Kujot]

I don't know why te response was removed, but it seems that there may be some issue in firmware that causes these troubles.

@Aureliannn_ASUS did you habe a chance to review my reports?