EX6100 not working with my Linksys router

The EX6100 worked before with the same router.  I have tried to hook it up and it won't stay connected.  I have reset the extender, still not hooking up.  I go to my router maps, it says the extender is there, but nothing.  The companies blame each other, and they want you to buy their support or their extenders and modems.

Everything works on my modem, like phones, computers tvs etc.  Any help would be greatly appreciated.