Model :

Hardware Version : Not Clear

Firmware Version :

ISP :

I have been running with a TL-PA4010 and TL-WPA4220 quite happily for several months, with a TL-WPA-4010 connected to a TP-LInk TD-W8960N ADSL Router.
I just purchased a second TL-4220 and have spend many hours trying to get it working fully with no success.

The new TL-WPA4220 seems to be working OK with a wired connection and it is broadcasting a solid WiFi signal, but no devices can get WiFi authentication.
Both of the TL-WPA4220s have identical settings, apart from different manually set IP addresses.
From my PC, I can reach and manage both TL-WPA4220s from my laptop through the wired network.

I have tried using the same SSID as the Router and different SSIDs for the Router and two TL-WPA4220s
I have tried putting all three on the same channel (with same SSIDs) and on separate channels (with the same as well as different SSIDs).

The outcome is the same - a good WiFi signal, but nothing can connect.

How can I tell if the new TL-WPA4220 is faulty, or if there is a problem elsewhere on the network?