Hello@ShNoorliza ,

Welcome to our community.

What is the model number of your device? Please refer to How to find the model number of your TP-Link device; How to find the hardware version on a TP-Link device.

Is it your first time setting up the router?  If yes, please refer to TP-Link Router Quick Setup.

If the router had internet before, and the red light indicates that the router has lost internet. Please try the following suggestions:

 1. Determine whether your router or ISP is the issue by connecting your PC directly to the modem to test internet access. If the Internet is not working, please get in touch with your Internet service provider (ISP).

2. Turn off the Modem and the Router, then power on the Router. Could you turn on the modem once the router is fully powered on?

3. Log in to the web UI via http://tplinkwifi.net and follow the Quick Setup to set it up.

4. Please go to Advanced > Network > Internet > Mac Clone to clone the MAC address of your PC.  How do I configure MAC Address Clone on my TP-Link Archer Router?

Best Regards.