Hello @Antoanish ,

Welcome to our community.

First of all, please check the router's Internet LED:
   • If the Internet LED is orange or red, there may be an issue between your ISP and the router. Please search for troubleshooting steps for "Router Internet light red/orange".
   • If the Internet LED is off, the physical connection between your modem and the router may be disconnected. Please try replacing the Ethernet cable.
   • If the Internet LED is green (indicating the Internet connection is normal), proceed to the next steps.

Check Access Control settings:
In the web interface or the Tether app, verify the Access Control settings to ensure your device is not accidentally blocked.

Check Parental Control profiles:
In the web interface or the Tether app, check the Parental Control profiles to make sure the device is not included in any profile that might be restricting access.

For wired devices:
If you're using a wired connection (PC, TV, etc.), double-check the Ethernet connection between the device and the router. In the web management interface (http://tplinkwifi.net), go to Network Map > select the Router icon > scroll to the bottom > Ethernet Status, and confirm the link status of the corresponding LAN port is up