Cant make VPN connection work network behind Meraki MX100 thru new Comcast Business Internet circuit

We recently added a Comcast Business Internet circuit as a backup Internet line on our Meraki MX100.  We were assigned a comcast gateway device and 15 static ip addresses for different services we host that our users require access from the Internet.  The problem is that we cannot make a VPN connection to our lan thru the comcast gateway device.  Worked with Meraki support on the issue and everything is fine on the Meraki side they say that VPN traffic isn't making its way thru the comcast gateway device.  We have a Verizon Internet line on a different wan port on the Meraki firewall and have no trouble with VPN connections, but when we fail over to the Comcast line everything works fine except for VPN access.

Did research and found a few settings on the comcast gateway device to supposedly disable the comcast firewall and pass all traffic to our Meraki firewall but that hasn't worked after several tests.  I also tried setting the comcast gateway to bridge mode, but I quickly found out that I lose access to the 15 statically assigned IP address that we need for our servers.

Do I need to have Comcast replace the gateway device with something that can successfully pass all traffic to our Meraki firewall and still be able to maintain the static ip addresses that comcast assigned for our use? Are there alternative comcast gateway devices we can try?