Connect to Server iPhone

The screenshot you posted hasn't been taken from an iPhone 12, but from a earlier iPhone model.

That said, when you see that message, it means that you do not have Internet access, neither using cellular data, nor wifi network. It can be a temporary glitch, appearing when you loose your data connection.

Check with your cellular provider if your traffic plan plan is okay, and/or verify your modem router connections.

If everything seems okay, I suggest that you try to reset your Network Settings, going to Settings > General > Transfer or Reset[Device] > Reset > Reset Network Settings. This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you've used before, but no other data is affected.

When done, restart your unidentified iPhone model.

Regards

Giulio

You are welcome.

Well, as already stated, resetting your network settings also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you've used before ON YOUR IPHONE.

Be aware that if you're using VPN connections I would try to turn them OFF completely.

Also, you wrote:...do note that I get this message even when I am connected to the net...

Two things:

1. being connected to a wifi-lan-etc. net(work) doesn't necessarily mean that your device has Internet access.
2. since, when you get that error message (are you sure that you get that same generic error message?), you are not able to identify what app is trying to connect to a (unknown) server, are you using "push" email notifications? or do you have other apps open in background?.

I suggest hat you force close ALL apps, and test your iPhone 12 without any connection except the main app using Internet (i.e. Safari, YouTube, AppStore, or similar).

Please let us know your test results.

Giulio