What's the firmware version indeed? http://www.tp-link.com/en/download/TL-WDR4300_V1.html#Firmware

The current firmware is old... Upgrade your router first. http://www.tp-link.com/en/download/Archer-C2_V1.html#Firmware Reset and reconfigure it to see if the problem can be solved.

What's wrong? :confused:

Check if WLAN AutoConfig is enabled or not. If the utility still doesn't work properly, you can try to connnect with Windows built-in utility to see if it works. http://www.tp-link.com/en/faq-306.html

W8961 has been configured properly and your PC can access internet by it? What's the hardware version and firmware version of your W8961ND?

Did you try to remove the network profile on your S5 and reconnect with the password? If it still failed to connect, what's the error message? You may try to disabled Wi-Fi security to see if it...