While poking at the myriad things my servers are doing, I noticed a lot of warnings from my mail server to Google and others, so I spent a few hours figuring it out.
It took some tinkering, a little trust, and acceptance that not all will be the same, but the new hard disk in the old desktop-turned-server is finally in use.
For years now we've had keyless locks on the doors on our home, but the one on the back stopped working with the app, and we never installed one on the garage.