Last time I logged in to my site successfully was 4/24/2012 - site is running version 6.1.4. I tried to log in today to upgrade to the latest, but neither my Host nor Admin users would log in. Though I could not remember resetting passwords for either, I used the Login dialog to request a copy of my password for each account. But, I got no email, and I get the error in the title in the EventLog table.
Both of those users email addresses are at the same domain as the site, and one of them is the same as the "Send From" address for the site.
So, I registered as a new user with my GMail address, and lo and behold both the new account and a subsequent password reset email arrived successfully. Not only that, I got an email about the new user signup in the Admin mailbox for the site - same one that the emails are sent from. That tells me it's not an SMTP problem.
I edited the dbo.Users table directly to update the email address for my Host account to my GMail address, then edited web.config (added a space) to force application reset. Then I tried to retrieve the password again for the host account, but again got a password_sent_failure and no email to the GMail account.
What am I missing?