WiFi Calling "REG99 Unable to Connect" error and Other Question Regarding Handoff topic

I'm getting the WiFi Calling "REG99 Unable to Connect" error when my Note 4 connects to my Home Wireless Router. I use Verizon FiOS at home and have the Quantum Gateway Router. I have the wireless functionality disabled on the FiOS Router and enabled on my Netgear Nighthawk. Can this be why I'm getting the error?

Also, how has your experience with the handoff feature in WiFi calling?