How to Resolve Common AES Response Messages

July 15, 2025

Note: This message is sent to all AES Updates subscribers and is for educational purposes only.

When submitting your Electronic Export Information (EEI) to the Automated Export System (AES), you can receive different response messages: Fatal, Compliance, Verify, Informational and Warning.  It is important that AES filers address and/or correct Response Messages as soon as they are received to comply with the Foreign Trade Regulations. 

To help you take the appropriate action, here is guidance on how to address one of the most frequent Response Messages that were generated in the AES for the previous month.

Response Code:  628

Narrative:     1^st Unit of Measure Code / Schedule B/HTS Mismatch

Severity:       Fatal

Reason:        The Unit of Measure (1) reported does not match the Unit of Measure (1) required for the Schedule B/ HTS Number reported.     

Resolution: The Unit of Measure (1) must match exactly the Unit of Measure (1) prescribed by the Schedule B/HTS Number reported.  See Appendix K – Units of Measure Codes

Verify the Unit of Measure (1) required for the reported Schedule B/HTS Number, correct the shipment and resubmit.

For a complete list of the AES Response Codes, their reasons and resolutions, see Appendix A – Commodity Filing Response Messages.

As a reminder, filers have multiple resources that they can use when filing EEI to the AES.  You can access User Guides, Walk-through videos and other resources at our website.

Please contact the U.S. Census Bureau’s Trade Data Collection Branch for further information or questions.

Telephone: (800) 549-0595, select option 1 for AES

Email: askaes@census.gov

Online: www.census.gov/trade

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