Hi,
Thank you for enabling debug and providing the details. The screenshot confirms the issue: the customer's phone number contains invisible Unicode control characters. Specifically, it has a LEFT-TO-RIGHT EMBEDDING character (U+202A) at the beginning and a POP DIRECTIONAL FORMATTING character (U+202C) at the end. These are invisible in normal display but they are included in the data sent to Authorize.net, and they cause the SHA-512 hash to not match.
This typically happens when a customer copies and pastes their phone number from a source that includes bidirectional text formatting (for example, from certain mobile apps, contacts, or web pages).
To fix this customer's account, edit their billing and shipping addresses in HikaShop and clear the phone number field, then re-type it manually. That will remove the hidden characters.
To prevent this from happening in the future, you can add a regex validation to the phone field. Go to HikaShop > Display > Custom fields, edit the "address_telephone" field, and in the Options tab, set the regex to:
This will only allow numbers, spaces, plus signs, dashes, dots, and parentheses in the phone number, and will reject any invisible characters or letters.