Fixed

Rob,

Are you deploying the firewall in Bridge Mode? In Gateway mode you don't need the above mentioned rule, try accessing the firewall from LAN zone, I guess there is MAC binding configured upstream

Navigate to System> Network> Interfaces> PortB:

Network Zone: WAN
IP Assignment: DHCP

Advanced Settings:

Interface Speed: Auto-Negotiation (Default)
Override Default MAC Address: Add MAC address of old firewall public interface

Save.

Hope that helps.

Hey Guys, thanks for the replies. I removed the rule that was said to only be effective in Bridge mode, as I'm trying to set this up as a Gateway. I tried messing with the machine again last night, with the same result.
My Port 3 interface for WAN states: Connected 100Mbps - Full Duplex Auto-negotiated.
IP - NA
DHCP

I tried removing the greyed out "128.0.0.1" for the Gateway IP, but that didn't make a difference.
I also set this interface up statically with the outside address I receive currently from my working Firewall(clearos). Set up statically, I'm not able to get to the outside.

I tried changing my MAC address to possibly show the ISP the machine or adapter has changed. That didn't help either. At this point I'm actually just swapping the hard drive out of the machine that's working as my Firewall, with the Sophos XG configured one.... I wish I could get this to work. I would love to be able to use the features included. Also, I love the UI. If anyone has any other ideas, please let me know. I've rebooted... I've also power cycled my ONT, with no luck as well. Thanks all.

Thanks.

Hey Rob. In future, please don't remove the text of the original post when your issue is solved. Maybe this thread could have helped someone else in future, but now people won't know what the original issue was.  These forums are a community.  It's not just about helping individuals, it's about helping everyone, past, present, and future.