@meraydin 

Okay, I understand that you are experiencing frequent connection drops every 5-10 seconds when connecting your laptop to the main SSID of your Deco Mesh network (X50 series), but the guest network works perfectly. You also mentioned that forcing your laptop to use the 2.4GHz band did not resolve the issue, and this problem did not occur with your previous Deco model.

Based on your description, this appears to be an unstable connection issue affecting client devices on your main Deco Mesh SSID. Here are some troubleshooting steps you can follow:

1. For unstable connections on client devices (such as laptops, PCs, phones, IoT devices) while all Deco units show green lights:
    • Check your device settings in the Deco app:
        1) In the client list section of the Deco app, select your laptop and verify that 'Speed Limit' is disabled and that 'Mesh' and 'Connection Preference' settings are not mistakenly configured. The 'Mesh' option should be 'on' and 'Connection Preference' should be 'auto' by default.
        2) In the 'Parental Control' section of the Deco app, ensure that your laptop is not accidentally restricted by any parental control profiles.
        3) Make sure your laptop is connected to the nearest Deco unit with a strong signal and is using the 5GHz band if possible, as 2.4GHz is not recommended for high-speed devices. You can try turning Wi-Fi off and back on to reconnect.

2. Additional steps:
    • Ensure the Ethernet cable between your main Deco and the modem/router is securely connected. Try replacing it with a new cable if possible.
    • In the Deco app, go to MORE > Internet Connection > IPv4 > DNS Address, and change the DNS servers to 8.8.8.8 and 1.1.1.1.
    • If you have satellite Deco units, make sure they are placed in open areas and not inside cabinets or corners. Move them closer to the main Deco if needed.
    • Open the Deco app and go to MORE > ECO Mode (if available), and ensure ECO Mode is turned off.

3. For 2.4GHz IoT devices:
    • If you have many Deco units and many IoT devices, try temporarily powering off some units to see if this improves stability.
    • If your Deco supports it, go to MORE > Wi-Fi Settings > Advanced and set the 2.4GHz Channel Width to 20MHz to reduce interference.
    • Use the 'Network Optimization' tool in the Deco app to optimize your Wi-Fi channels.

If you continue to experience issues, please contact TP-Link support and provide details about the troubleshooting steps you have tried.

For further information, you can refer to this FAQ: https://www.tp-link.com/support/faq/2718/