This is with the latest Emacs Version 27.2 (9.0) for Mac OS X:
error in process sentinel: Error retrieving: https://elpa.gnu.org/packages/archive-contents (error connection-failed "connect" :host "elpa.gnu.org" :service 443) [2 times]
I can access that address in a web browser fine.
.emacs file contains a basic package configuration:
(require 'package) (add-to-list 'package-archives '("melpa-stable" . "https://stable.melpa.org/packages/") t) (package-initialize)
I see others have this issue, but it's a very different issue, the answers suggest this was fixed in Emacs 27+, which I'm already using.