What does a 503 error mean? Leroy Esterhuizen August 16, 2021 14:13 Updated Follow This is a timeout error receive by merchants on 3D Secure when attempting to do a 3D Secure lookup. Related articles Adumo Online API Response Codes What does a 9001 processing error mean? What is 3D Secure and how does it protect me against fraud? What does error 9010 mean? Comments 0 comments Please sign in to leave a comment.