Hello @Aead200Mohamad ,

If you are experiencing difficulties with the Tether app login your TP-Link Archer Router, please follow the steps below:
    1.Make sure the phone is connected to the main network of the TP-Link device, not the guest network or other networks.
    2.To upgrade the TP-Link devices' firmware to the latest version, you may log in to the TP-Link web management interface to check for updates.
    3.Turn off any VPN application on your phone.
    4.Turn off the mobile/cellular data on the phone.
    5.Reboot the TP-Link device.
    6.Close the Tether app completely (kill it in the background) and reopen it.
    7.For iOS devices, please enable "Local Network Access" permission for the Tether APP (Settings > Tether APP > enable Local Network Access).
    8.Ensure no other devices are accessing the management page.