R7000 router, ex 6400v2, then ex 6120. ex 6120 fails to connect to internet

[Boiler1Maker]

Hello folks.  This is what I'm trying to do.

My house is a long 1600 sq feet, with my router in the laundry room, about 100 feet from my computer.

So, I purchased an ex6400, but didn't quite get me to my computer.  Very weak signal.

So, I figured I help it out a bit, by purchasing the ex6120.  Didn't need much help, just a boost.

TROUBLE:

ex6120 shows on my list of connections (Windows 10), as ***ext, ***ext.  Cool!  Looks good, right?

Nope.  Neither 2.4 nor 5, even though I have a very strong signal from the ex6120, connect to the internet.  CONNECTED, BUT NO INTERNET, SECURED (or some such thing)

Now I'm lost, been trying for about 5 hours now, reading through the internet.  One person says the router is blocking it, but I can't find that, nor a way to fix it.

Ideas?