This took way too long to figure out and it’s my own fault as I do have a good understanding of networking.
When you order additional IP’s from So You Start, you’re usually giving IP’s in a different range the main IP address of your server. This might confuse some because of how traditional networking states you have to be in the same subnet as your gateway.
This causes problems for deploying virtual machines when using Xen and Ubuntu 18 as it has moved over to netplan. The problem lies in the fact you shouldn’t be able to reach your gateway out of your subnet.
So you have to do the following so that netplan is able to understand how to add the gateway properly.
Here’s the wonderful thread it came from