Ah, it is an AA-linked AMEX / American Express problem. This thread will be sent over to the appropriate credit card forum, as it is not airlines-related.
AmericanAirlines, thanks for your suggestion - but it seems not to be an AAdvantage-related issue. /Moderator
(Yes, there
are characters in names and addresses that are not acceptable or usable in different countries and IT systems, often "é" but certainly others - why it was earlier recommended to use the USPS site to validate, and you can play with characters - or their omission - that will allow a validated address.)
Originally Posted by
norf9
Also your name cannot contain "." "-" "'" or any other non-letter character. The error it gives you is "The name you entered is invalid". No, you are invalid AMEX!

It's like the AMEX IT team has never opened a phonebook.