The extender appears to be connected to the router. ( I have used the wps method and the tether application method) The lights of the extender remain solid blue, and it appears I have a new extended network apart from the host network. But when I try to connect my devices (mobile phone, tablet and a Samsung tv) to the extended network, using the same password as the host network, I get an "incorrect password" message. Using the tether application I managed to change only the extended network name (not able to change the password). This way I was able to connect the phone to the extended network. But still no luck with the tablet and the tv (the tv appears to be connecting without problem to the host network, but the signal is weaker, because the host is more far away from the tv). 

I tried to connect the extender to the router with an ethernet wire thinking of the solution to upgrade the firmware. 

Using the link https://tplinkrepeater.net/ I didn't manage to get your help.

I would appreciate your help. I would like also to know if there is a service location for tp-link Greece.

Thanks in advance