Hello @SalmanSyed ,

Thanks for contacting our community.

Here are some steps you can follow to troubleshoot steps:

If all devices are unable to connect to the router's Wi-Fi network:
1. Please double-check your SSID and password, and ensure there are no extra spaces at the beginning or end of the SSID or password.
2. Log in to the router's web management interface (http://tplinkwifi.net), go to Advanced > Wireless > Wireless Settings, and try changing to a different wireless channel.
3. Reboot the router again.

If only specific devices cannot connect to the Wi-Fi network:
1. In the Tether app, go to MORE > Block List to ensure the device is not mistakenly blocked.
2. Log in to the web management interface, go to Advanced > Wireless > Wireless Settings, and disable "Smart Connect".
3. Change the encryption method to "WPA2-PSK/WPA-PSK" to improve compatibility with older devices.
4. Update the driver or operating system of the client devices.