TD-W8950N has V1 only... Broadcom chip...

What's the model number? Firmware is up to date? How about status of RE light? Connecting to the extender, did you check IP address, default gateway obtained?

Except devices running in Windows 10, are there any other wireless clients available for you to test the extender running properly or not?

After firmware upgrade, did you reset the router to factory defaults first? Your topology is as below, right? MAC is the only client in local network? Can you try to login the web interface on...

Check local area connection on your PC. Ensure it is using DHCP and IP address, default gateway etc. are obtained automatically...

I see... Update it here if there is any progress...