I'm trying to buy a ticket on the app and I can't complete the security challenge

If you're struggling to complete the security challenge that pops-up when you are making a payment, you need to contact your bank or card issuer to request assistance. The security challenge can take a number of forms, and First Bus present these directly from your bank or card issuer. It could be an SMS message is being sent to the wrong mobile number, or your bank is expecting you to use their mobile app to approve the transaction.

Only your card issuer can resolve this. If you can't complete the purchase, you could try a different card, or buy your ticket on the bus using your card.