We’re still working with our third-party provider on a permanent solution.
As a temporary workaround, while this issue is being resolved, please limit Sandbox testing to 3DS frictionless flows only and use 3DS frictionless test cards.

For more information and a list of supported test cards, please refer to our documentation:
https://support.bluesnap.com/docs/3d-secure#test-3-d-secure-2

Production 3DS processing remains fully operational.

3DS is temporarily unavailable in the Sandbox environment due to ongoing maintenance with a 3rd party service provider. 3DS remains fully functional in Production.