In most cases, errors preventing the registration of a UPS account are related to a mismatch in the information entered compared to what is on file with UPS.
Review the article Where can I find my contact information for UPS registrations? This article will walk you through the process of finding the correct contact information to use when adding your UPS account.
If you are receiving the following error:
Request cannot be processed, please contact UPS customer service at 1-888-851-4901
This means that there is a credit issue with your UPS account, and you are unable to ship packages either on UPS.com, ShipStation, or any other application using your UPS account.
Your UPS account representative and the regular UPS customer support team will be unable to assist you. You need to call the number provided and leave a message. The UPS credit department will follow up with you to resolve the issue. When the credit hold is removed, you will be able to register your account in ShipStation.