If your card on file uses 3D Secure (3DS), such as Verified by Visa or Mastercard SecureCode, you'll need to go through an additional verification step in order to complete the payment.
In this step, you're directed to an authorization page on your bank's website, where you'll be prompted to enter a verification code or password.
If this verification step fails when purchasing additional seats for your team, the payment will also fail and you'll see the following error:
Verification failed: The seat wasn't added because the card security check failed. Please retry the verification process, or try the payment with a different card.
When this error occurs, the new member isn't added to the team.
To clear this issue and add the new member, you'll need to enter the correct verification code. Alternatively, you can try adding a different card without 3D Secure.
If the issue persists or you have any additional questions, please let our Support team know.