Set up MullvadVPN but I can't get online

I used Mullvad’s own guide to set up MullvadVPN on Qubes.

I am using a mostly fresh install Qubes with all the default qubes.
During the process, specifically during the part where I had to add the DNS hijacking rules, I did find default-dvm able to connect online through the VPN but after I finished everything, I couldn’t connect online.

So I wonder where I went wrong.
I am trying to use a multi-hop wireguard connection.
The qube I’m using to connect to my VPN is called sys-vpn and uses sys-firewall as its NetVM.

When I configured the stuff, I got a warning message telling me the NetVM is different from the default disposable template’s (default-dvm) NetVM so I changed its NetVM to sys-vpn.

I know I’m not giving much to go on but if you could ask me any questions about what I did, maybe we can narrow down the problem.

Edit: I’ve reset all my qubes NetVM’s back to sys-firewall and I was able to connect online again, albeit without a VPN.