Magento 2 – Not Receiving Email After Order

I have this demo Magento 2 store (ver. 2.4.4) built on a Debian server and for some reason I’m not receiving emails after I make an order.

In Stores > Configuration > Sales > Sales Emails I have this:

My /etc/postfix/main.cf file:

I didn’t even receive an email when I first installed Magento 2 on my server, so I had to disable the 2FA module in order to login to the backend for the first time.

Any help would be appreciated.