IMAP/Outlook2007 Issues

Weening myself from corporate Exchange Servers, I’m trying to get IMAP working with Outlook 2007. I have two issues:

  1. Folder sync doesn’t seem to work all of the time.

  2. Mail send fails with this error: “Task ‘’ - Sending’ reported error (0x80070057) : 'Could not complete the operation. One or more parameter values are not valid.”

However, when I click Outlook’s “Test account settings…” button. Send and receive work fine; I receive the sent “Microsoft Office Outloot Test Message” just fine!

Any suggestions on what to check?