There are a few steps you can try to fix the ASUS router WAN red light:
- Check that the router is properly plugged in and that the outlet is working.
- Try restarting the router by unplugging it from the power source, waiting a few seconds, and plugging it back in.
- Check that the cables connecting the router to the modem and other devices are securely plugged in.
- Try resetting the router to its factory settings by using a paperclip to press and hold the reset button on the back of the router for 10 seconds.
- Update the router firmware to the latest version available.
- Try connecting to the router using a wired connection instead of wireless.
- If none of the above solutions work, contact ASUS support for further assistance.