C6900 No Internet connection with Verizon

> We cannot connect to the Internet with the Nighthawk C6900 cable modem
> router. [...]

   "cannot" is not a useful problem description.  It does not say what
you did.  It does not say what happened when you did it.  As usual,
showing actual actions (commands) with their actual results (error
messages, LED indicators, ...) can be more helpful than vague
descriptions or interpretations.

   What, exactly, were you expecting to connect to what, exactly?  What
did Verizon give you to connect to?  What sort of modem/router/whatever
did Verizon try to sell you?

   The C6900 is a "Cable Modem Router".  Is Verizon a cable-TV-type ISP?
I thought not, but your relationship with them is closer than mine.

> [...] Let us know if Verizon does not support this router, [...]

   Did you try asking anyone at Verizon?

> [...] though it should.

   Says who?  Why?  Because you have one, and you wish that you could
use it?  Not a very powerful argument.  I doubt that it will persuade
the hardware.