This problem has gotten significantly worse since Yosemite.  It seems to be related to Apple's KeyChain being corrupted.  When repairing my KeyChain, the problem is identified:

          Item “imap.aol.com” has unspecified value for port attribute

I'll repair the keychain, but 30 minutes later, I'm presented with the dialogue to reenter my password for the AOL account.

Outlook is prevented from taking a Nap (a fix that has been suggested elsewhere)

Any idea how to correct this?