First, please disable the IPv6 option and then perform standard troubleshooting.
To disable the IPv6 option, please refer to the following methods:
Method 1:
Using the Mi Home/Xiaomi Home APP: Go to the router’s page in the APP >> tap [Network settings] >> [IPv6 network settings] >> disable it.
Method 2:
Using the web interface: On a mobile device or PC, open a browser and enter 192.168.31.1. Enter the management password >> click [Common settings] >> [Network settings] >> scroll down to find [IPv6 network settings] and disable it.
You can also try the following troubleshooting steps to identify and resolve the issue:
1. Reboot both your modem and router or use a wired connection to check if your Internet connection is stable;
2. Reduce the connected devices to decrease the load of the network;
3. Change the Wi-Fi channel or band to reduce the wireless interference. Switch between 2.4GHz and 5GHz bands;
4. Ensure that the router's firmware is up to date. You can check for updates via the Mi Home/Xiaomi Home APP or the web backend interface;
5. If only certain applications or web pages are slow, try clearing the APP or browser cache, restarting it, or reinstalling the APP to ensure it's not causing the lag;
6. Perform a factory reset if necessary. Remember to back up your settings if needed;
7. Please contact your Internet service provider to ensure there are no outages or issues on their end.