Wireguard no internet and certificate error

[chucklessduck]

Ok, so I have been following this guide. https://docs.opnsense.org/manual/how-tos/wireguard-selective-routing.html

I have almost everything working.
Wireguard is connected and working
I have two computers set up and I am trying to only send one of them through the Wireguard tunnel. At the moment the one computer is getting internet. The other computer that is routed through the Wireguard tunnel is not getting internet. I keep getting a page that says "the network you are using may require you to visit its login page." I have no idea what this means. I have attached the firewall rules and nat rules.

I am new with this so any help would be great.

Edit: I am definitely leaning towards the odd RFC1918_Networks config is the issue but I have no idea.