Transaction Declined Message for one contact

I have tried many times today to send money to one of my contacts through Apple Cash. I keep getting “Payment Failed” with a follow-up message of “Transaction Declined: The transaction cannot be completed at this time.” We have both changed each other’s contacts in our phone to each other’s legal names. I sent money to one of my other friends during this fiasco to see if it would work for another contact, and it did. My Apple Pay sent her money and she was able to send it back to me. I have used LTE and also two different WiFi networks. I have tried different amounts. We cannot figure out what is going wrong.