I recall years ago that autoconfigure for email accounts worked in iOS Mail/macOS Mail.app when MacOS X Server was a thing. The protocol is supported by Outlook and Thunderbird and some other apps as well. Using WireShark, I can see there's some network activity from Mail.app when trying to get to the second step of adding a new email account. The most documentation I've been able to find online is making a mobileconfig file which works but is cumbersome in comparison to how it works with Outlook and Thunderbird. If there's any kind of documentation on autoconfigure for macOS/iOS, I'd like to see it so I can help with Virtualmin development team fix their implementation of autoconfigure/autodiscover to properly work with iOS/macOS.
Help anyone?