Unable to pay online—app says I must pay in person

Whenever I attempt to pay my Xfinity bill using the phone app, I see a message saying: "You'll need to make a payment in person. Please visit an Xfinity store near you." I hear this sometimes occurs when Xfinity's systems suspect fraud on an account however there is no fraud occurring with me. How can I get this restriction removed so I can pay my bill using the app again?