Ok, got some clarification on this from Enom. Maybe it will be helpful to some of you. It looks like the PO box issue is for Mastercard.
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Here is more information regarding our new address verification process:
After you submit a purchase request, we send a command to your credit card
company for a pre-authorization for that amount. If this is approved, our
new address verification program will send another request to your credit
card company to confirm personal information. If you receive an error,
please make the update and try again.
For each submission you send, your bank will process the pre-authorization
request first. If the address verification fails, we will NOT submit a
charge against the pre-authorization, and your bank will automatically
remove the hold on your money between 5 and 14 days (all banks differ, you
will need to ask your bank about the timeframe when they release the hold on
funds.) We do not have an electronic way to remove a pre-authorization.
If you get an error that your ADDRESS does not match:
You will need to enter your address as it appears on your credit card
statement. If you have a retail account, please go to: MY ENOM, MY INFO
and make any changes necessary. Then you can reattempt to register or renew
your domain names. It if does not approve, we are unable to force it
through for you; therefore we suggest you try a different card or send a
check for your purchase.
If you have a P.O. Box, please enter in the following universal format:
P. O. Box 322
If you are using a VISA it should process if you are using this format. If
you are using a MasterCard, P.O. Box numbers cannot be used with address
verification software. We are working to find an alternate verification
solution for M/C cardholders that use a P.O. Box for your billing address.
In the meantime, you will need to either enter a different credit card or
send a check to pay for your purchases.
If you get an error that your zip code has failed:
If you are in another country, you should be able to enter your postal code
or country code. If your country does not use one, you can enter NA.
If you get an error that the CVV2 number has failed:
Double check the back of your credit card. The CVV2 number is usually
printed in your signature area, it is printed after a set of numbers, which
may also be your full credit card number. A full explanation is provided on
your MY ENOM, MY INFO page in the Credit Card Information section.
We truly want your registration to go through, and hope these suggestions
will help process your order. Unfortunately, there is not a way for us to
override a failed verification. Perhaps another card will process if you
cannot get the current one to complete.