Paid for PlexPass and one TV can't find it.

Why does one TV find he Plex server on my Netgear Nighthawk x10 and the 2nd TV can’t find it?

Plex Pass isn’t a thing to find. It is not required. Buying it will won’t fix any network issues with an app finding your server.

Explain your network setup, what sorta tv do you have, etc, etc please

Here’s a generic solution that may, or may not help:

I am still trying to install PlexPass on the routerlogin screen of Netgear x10.

You mean the Plex server I assume on the router?