Outlook Error: Cannot open your defauilt e-mail folders

Problem

1. The action cannot be completed. The connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete this action.

2. Cannot open your default e-mail folders. The information store could not be opened.

Solution:

1. Create New Outlook profile

2. Go to program files --- Microsoft Office—outlook.exe --- Prop---Compatibility mode

3. Compatibility mode--- Uncheck that

Your message did not reach some or all of the intended recipients

Solution

One of my user faced the same problem with Outlook 2007 on a office computer configured for Exchange Mailbox access. I resolve this issue by simply choosing "Resend This Message" then double clicking the offending email address, clicking the "Internet Type" button to change type to SMTP then OK.  It sent the mail fine.