Quoting from Nerijus Baliunas's mail on Mon, Nov 04, 2002 at 02:00:09AM +0200:
Attached is a patch which changes the auth method to password if STLS
fails.
Will user know that STLS/STARTTLS failed (from the logs)?
In verbose mode, yes. The message used to come in normal (and silent!)
mode also (O11 in FAQ), but it was removed by demand.
Sunil Shetye.