What to do if both 2.4 GHz and 5 GHz Wi-Fi on the Xiaomi router are disconnecting simultaneously?

Check the router system version. Make sure your router firmware is up to date. You can verify the latest version at miwifi.com.
If only one device is disconnecting, the issue may be related to the device itself and should be troubleshooted on that device.
If all devices are disconnecting, please refer to the following steps to troubleshoot:
1. Check the router’s signal strength and remove sources of interference. Keep the router away from microwave ovens, Bluetooth devices, metal doors, and wall-mounted weak-current boxes.
2. Try updating the router’s network name and password. Enabling [Pass-wall performance] can improve coverage.
3. Change Wi-Fi channel, switch to the least congested one.
4. Ensure the number of connected wireless devices does not exceed half of the theoretical maximum supported by your router.
5. If issues persist, reset the router and reconfigure it.
6. If none of the above steps work, please contact the after-sales service center for further assistance.