Which version of Mail-in-a-Box are you running? What is the content of the debug log you mention? Does the System Status Checks page of your Mail-in-a-Box report errors?
Perhaps this answer of Alento will help.
Which version of Mail-in-a-Box are you running? What is the content of the debug log you mention? Does the System Status Checks page of your Mail-in-a-Box report errors?
Perhaps this answer of Alento will help.