Did you reset the router to factory default and reconfigure it? If the problem continues, maybe it is defective.

We can add 6 PCs one by one or with either IP address or MAC address. Also, we can use IP range of 6 PCs. What are you trying to input under LAN Host? You can contact TP-LINK support team directly to...

Which router are you talking about? Different routers may use different chipset. If you need a broadcom one, you may confirm with TP-LINK support team and describe all your needs in details....

When you cannot connect, can you log in web interface of C5? Any device connected to LAN port of C5 can access internet all the time? Try to change Address Lease Time to 2880 and test. BTW, what's...

Can you see URL address as the above screenshot?

Powerline devices should work in a pair as least. Did you refer to TL-WPA281KIT? PA2010 in the kit will be connected to the main router and WPA281 can be placed in the room where you want to boost...