Verizon LTE Network Extender

The cell service in my house is terrible so Verizon sent me an LTE network extender. This was to replace a previous one that went end of life and worked just fine. Upon installation, I received a Server Error 9A stating to check LTE or firewall settings. I contacted Verizon and was told that this is a known issue with Xfinity. The Verizon tech told me that I will need to contact Xfinity support and likely speak to multiple people because, while it is an easy fix, I would struggle to find someone who understands the issue. He wasn’t kidding! I spoke to three different people last night (all told me to reboot my router) and none of them would elevate me to advanced tech support. This is a known issue that I found on Reddit and other online forms.