Had to replace the gateway.

The printer (HP m201dw pro) tries to connect to the COX Panoramic router but fails with a message that states "Router must be 2.4g and not 5." I know of no way to tell the router to switch to 2.4. The App does not want you to use separate 2.4 and 5 but rather let it do the sorting.

It cannot see the 5ghz, only the 2.4. The error message doesn't make sense, since the printer only has 2,4 ghz, 

I think the coder for the setup program was just using a process-of-elimination.  The printer assumes you have a wireless network but can't detect 2.4 GHz...so what other frequency would be left?  5 GHz.

If the Panoramic no longer allows you to have 2 separate wireless networks, the Panoramic is doing you no good.  Get rid of it.

Yes. Seems about 100 times. I did a chat with Cox today and he gave me a number to call since I'm a preferred customer whatever that means. Im calling tommorrow. Ill let  you know.

The ONLY ports that are blocked are covered here - https://www.cox.com/residential/support/internet-ports-blocked-or-restricted-by-cox.html 

They cannot be altered in any way. 

Thats exactly what Cox said but they didn't know for sure. None of the tiers could figure out my port problem.  According to the Tier 3 guy the routers software had to be borked not allowing any ports to be opened even when he had me unplug it for 10 minutes and reset it back to factory default. Replacing the already replaced router solved the problem. The defective router worked everywhere else except those few ports I needed. 

Never trust a refurbished unit to be working.