Apparently there's still more to see if you dig deeper, but I'm unfamiliar with Chrome's UI for invalid certificates.

If you can open your terminal, this may be easier:

% openssl s_client -connect web.dev:443

It will hang (I guess awaiting more commands) but you can use Control-C to kill the connection.

The gist below has the first several lines showing what you should see.

https://gist.github.com/macintux/68ab1317d4b7677951069baf95c...

OK, I think I see what's happening. There's some other software that overrode the *.dev cert. I'll remove that and see if it works. Thanks for your help!

Huh, that's...unexpected. My best guess was that somehow the root certificate was missing from your computer's trusted certificate store.

Glad you got it sorted, happy to help.

It was a fairly common issue when .dev first launched. https://andycroll.com/ruby/clean-up-broken-dev-domains-after...

Aha, interesting. Thanks.

Yup, that's exactly what happened. Thanks to both of you for your help! I really appreciate it. This was driving me nuts!