@RFP I see, that's unusual. Which band you use for WDS - 2.4 GHz or 5 GHZ ? Do you have for WDS mode these options:

@GA_Polo What's your C6 WAN/Internet IP address ? Is that the private IP address that has been updated into the no-ip database ? If that's the case then you have two options : 1) If it's possible try...

@felixk If that's the case, then reporting the issue, definitely would help TP-Link folks to further trace what causing it.

@felixk Kevin's idea was to setup DMZ to the host in question, try to establish a VPN connection and see if it works (without trying to open the 1701 port). What I wanted to point out is the...

@RFP Did you try to ping C6 from a device connected to C80 ? That's rather strange behaviour - everything works, but no access to the extended router. I would suggest that you have changed the web...

@RFP " Can't find it either in Network Map (Archer C80 main router's management page) or DHCP Client List. " If the C6 is with static IP address I believe this is normal. Why don't you access the C6...