Email Notifications Issue: Host or Domain Not Found

I've been troubleshooting this for nearly 24 hours now. Was working fine until an update happened. Postfix file hasn't changed (set to my router's ip AKA default gateway). I tried changing it to 8.8.8.8 but nothing changed, so I reverted it back. I am able to ping outside of the network with zero issues, as well as within the network. Checked if it was the smtp server, but it all checks out fine. Really scratching my head about this. Internet is perfectly stable.

Here are my settings (without giving my personal email).

Any further info needed let me know.

So I feel very stupid for this, but I found out the issue.

I had my router set a static route for the OMV server, while at the same time the OMV settings where set to static (with the same IP addresses mind you).
On the webpage I went to:
Network>Interfaces
Edit
Method: DHCP
and set it to automatically get the IP from the DHCP server. Since its already set on the router, the IP remains the same. Now everything works like a charm.

Spent DAYS troubleshooting these going through a variety of documentation, and it was just a simple conflict. Embarrassing.