On March 30, 2018 we became aware of a change in the email address validation rules that are being applied by Authorize.Net.
Previously, it was possible to create a customer in Chargify with an email address that contains a plus sign, such as
firstname.lastname@example.org, and also create a payment profile to store a credit card for the customer at Authorize.Net.
Recently, Authorize.Net began returning the error “email is invalid.” when we attempt to store a card for a customer with an email address that contains a plus sign.
This means that signups will fail if the customer supplies an email address containing a plus sign, and that new, additional cards cannot be added to customers with an email of this type. (Though card updates, which replace the card on file, do seem to work.)
Unfortunately, this is something that is outside of Chargify’s control. If your business is affected by this change, we suggest that you reach out to Authorize.Net support and request that they revert to allowing email addresses containing a plus sign.
You may also wish to comment on and follow this issue in the Authorize.Net developer support forum: https://community.developer.authorize.net/t5/Integration-and-Testing/Create-Customer-Profile-requests-with-emails-containing-a-symbol/m-p/62416