Microsoft CRM Quick Campaign throws an error: 0x8004020f

Sometimes you see weird errors in applications, below is one of those. A Quick Campaign fails when emailing multiple Contacts.

The Error:
"This Quick Campaign could not be performed due to an error: 0x8004020f. For more information, contact your system administrator."

Resolution:
Check and validate the email addresses being used by the contacts or accounts in the Quick Campaign. Sometimes when entering data people make mistakes like entering spaces in an email address or double @ symbols.