Is there any high power appliance near the powerline units? Have you tried changing the place where you plug? According to your description, it seems there is some high network or electrical...

it seems there is seldom single unit. Any wifi extender will work with it. Certainly, it's better to choose a similar power data speed. If the powerline speed is too low, it will decrease the whole...

Plug them into wall power sockets in a same room with your router. Then, try to repair them by pressing pair button for 1s one by one. If there is no success, you may try several times.

how about the LED status on the router? Or try to login with cable connection. If there is no success, it's better to contact tp support via call or email to ask for more help.

1. check whether your USB modem is compatible with the router. 2. if it's not, it's hard to say whether they can work together properly. 3. try to put the APN and dial number manually. Here you can...

Authentication failed, it means you put wrong username or password provided by your ISP. Double confirm the info or pay attention to the case sensitive.