Printing Issue NIGHTHAWK X4S DOCSIS® 3.1 C7800

I have a NIGHTHAWK X4S DOCSIS® 3.1 C7800 Cable Modem.  I have an HP Color LaserJet CM1312nfi MFP Printer.  I'm using a MacBook Pro running Mojave 10.14.4.  Printer has the most updated firmware.  MacBook was received last week and is just set up.  I also have a Dell laptop E series running Windows 7 Professional 64-bit.  

 

Network:  Cable Xfinity internet attachs to C7800 Nighthawk.  The Nighthawk connects to a few items and a switch/router to add ports. One wire runs to a Apple Airport Extreme with Time Capsule.  One wire runs from Apple Airport Extreme with Time Capsule to the HP Printer.  

 

All devices:  can see and access the internet and LAN.  Phones, PCs, Dish Hoppers, ADT Pulse, etc.  They connect either IPv4 or IPv6.  MacBook can save to Time Capsule, access all internet sites, etc.  Dell can do the same.  

 

Printing:  MacBook can see the printer.  Can set up the printer.  Can show the supplies available, etc.  BUT, the MacBook can't print.  It throws an error:  Unable to write print data Broken pipe.

 

The DELL CAN print without issues.  

 

Tried:  I have reboot all items on the network.  I have confirmed printer accepts IPv6.  I have confirmed that all items on the LAN respond, etc.  I have updated HP firmware.  I can't get anything to print from the Mac. If I DISCONNECT the netgear cable modem, and I use wifi Airport as the hot spot, then I CAN print from Mac to the printer.  So, I think the issue is in the cable modem?

 

Thanks for the help!

Doug