Happily, most owners (myself included) of a new iPad Wi-Fi+ 3G have had no problems setting up and activating the 3G service option. Most people, however, is not the same as all people. A perusal of Apple's discussion boards reveals an assortment of activation problems affecting a significant minority of owners. The origins of these problems appear to lie mainly with AT&T--rather than with Apple or the iPad.
Some of the activation glitches most likely amount to "opening day jitters." That is, with the initial rush of activations in the rear view mirror, and with AT&T learning to cope with the issues that cropped up, you are less likely to have a problem now than on the day that the 3G model first became available. If you nevertheless do have trouble getting 3G activated on your iPad, here is a rundown of the most common symptoms and their solutions:
No sign of cellular service
All goes well with setting up and activating an account. Despite this, you wind up with no cellular service, no 3G Internet connectivity. According to an Apple Discussions thread, there is a likely easy fix: Navigate to Settings -> General -> Reset and tap Reset Network Settings.
While setting up your cellular account or when first trying to make a 3G connection to the Internet, you get an error message that states: "AT&T is unable to process your request. We apologize for any inconvenience. Please try again later (Q5033)." You try again later, but the message persists. According to an Apple Discussions thread, the likely problem is that your newly created account is somehow not attached to any billing information.
One way to confirm this is by going to Settings -> General -> About. If no "Cellular Data Number" is listed, you probably have this problem.
To remedy the situation, AT&T must delete your non-functioning account. You can then make a second try at activating the 3G service, which should now succeed. The potential hassle here is that, at least according to several posts I read, it may take some effort to get AT&T to connect you to someone who can and will delete your account. If you have trouble with AT&T, you might decide to wait them out. Several users reported that a nonfunctional account was eventually automatically deleted (apparently because AT&T eventually detected that they had no billing address). At this point, the user could successfully complete a new activation.
According to yet another Apple Discussions thread, while entering data for your activation, you may get a message that says: "Please validate highlighted address information and retry." The problem is that your address is correct; the error persists no matter how many times you retype it. Without a "valid" address, you cannot complete the activation.
The exact cause here remains a bit uncertain. It appears to happen if AT&T determines that it has no 3G coverage in the region of your entered address (which is typically the same as your credit card billing address). This prohibition makes little practical sense, as you may intend to use the 3G connection at other locations. The presence or absence of 3G coverage where you live and/or work should not be relevant to opening an account.
One posting claims that AT&T has already made a change that at least partially resolves the matter: "There is now an option to enter a different service area address than your credit card address." If even this option does not help, you may have to change your credit card billing address, at least temporarily, to one that AT&T finds acceptable.
If you have this address error and remain uncertain exactly how to resolve it, read through the above cited thread. Several postings provide more detailed advice.
This story, "Bugs & Fixes: Troubleshooting IPad 3G Activation" was originally published by Macworld.