Make sure you have a certificate installed under System->Certificates. Also, under System->General, check if the WebGUI HTTP->HTTPS Redirect box is checked, and the certificate is selected as the GUI SSL Certificate.So https is missing. I don't if this has to do with the certificate issue or not?
Who knows? The upgrade process always does a lot of database stuff behind the scenes. To get things working again, you'll unfortunately have to do a lot of manual certificate processing, as your server doesn't have Internet access, which is what Automated Certificate Management Environment (ACME) (see Guide section 7.16.1) requires.what changed from U2.1 to U3.1 to cause this issue.
No reason at all this should be necessary; FreeNAS is perfectly capable of generating its own self-signed certs.You may need to fix this via ACME to get a real certificate.
There's no way you could have been using it on HTTPS if you hadn't.I never created a certificate.
Interesting; I don't recall ever seeing that behavior before. I wonder if it's a relatively recent thing, or if I'd just missed it. But in that case, very strange indeed that the private key would have gone missing.The Guide says FreeNAS will generate a cert on boot if one doesn't already exist