There are some questions on serverfault about setting up Thunderbird autoconfiguration and Outlook autodiscovery, but when using the default email client on Android (tested on three phones – v4.4 and v5), it still requires manual setup.
When I enter the email address and password and touch “Next” it says “Checking auto setup information…” but it doesn’t make any contact with the email server (I watched traffic on ports 80, 443, 587, 993).
So what protocol does the Android email client use for its autodiscovery? Where is it documented?
You appear to have hit a long-standing issue in Android. In particular Android will only load the autodiscover XML over HTTPS. If you serve it over HTTP then Android will refuse to even attempt to use it.
As described in the bug, Android does not use DNS SRV records to locate mail services.
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