USPS ID - v3 Cs-Cart says " Username exceeds maximum length."

CS-Cart says my USPS userid “Username exceeds maximum length” even though USPS accepts my user ID just fine. Any idea how to fix this?

Got this problem here too…get to figure this one out now.

My user id is 12 characters. How may do you have? I would think the number of characters is standard.

Where is USPS accepting yours at?