A number of iPad with Wi-Fi + 3G owners are reporting an AT&T error that leaves their devices without access to cellular data. According to an Apple Support discussion thread, affected users are seeing a message that states, “AT&T is unable to process your request.
We apologize for any inconvenience. Please try again later (Q5033)” during the cellular data account signup process.
The issue appears to involve the data/billing information not being received by AT&T, and therefore not being attached to the account. Based on user responses from the thread, those users dealing with the issue need to contact AT&T and have their ICCID number tied to the phone number assigned to their data account in order to get service; others have had success with replacing the iPad’s Micro-SIM card entirely.