Hello @Nakanak 

Thank you for reaching out to us and welcome to the TP-Link community.
 

Are all the three routers connected to the same modem router (the internet box from your provider)?

How about the internet LEDs on the Archer C50s and Archer C60? Are they all green or orange? If the internet LEDs are orange, that means they failed to generate the internet from the internet box.

What is the WAN Connection Type on the C50s and C60? Are all Dynamic IP? If there is no WAN IP address on the C50s/C60, please try following the troubleshooting suggestions to see if you can get the internet back:

What should I do if I cannot access the internet through Wi-Fi router?