A wrong mailing address is more than just headache -- it's costing the U.S. Postal Service millions annually, the agency's inspector general has found.

A program used by the U.S. Postal Service called the Address Management System stores the information that allows for the delivery of mail to more than 127 million address across the country.

A recent effort to reduce database errors in AMS data fell short, according to the IG. By not making address error corrections, USPS lost about $14 million in 2012 and 2013. Errors include wrong ZIP codes and out-of-date delivery routes.

Reducing the AMS staff not only added to the issues, but the Postal Service failed to make sure there was a process for employees to follow to correct errors in the system.

"Correct addressing is critical to reducing the costs associated with handling returned mail for the Postal Service and its customers," the report concluded.