For 3 weeks that I try to process plug-ins in my CART.
It fail at MasterCard step #2 (OTP code) send by SMS or Email.
4 Tickets are open at MasterCard on this mather, whitout any resolving by their programers.
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So going by your message, Mollie (the payment provider is not receiving the validation code that the MasterCard 3D server should be sending.
Regarding your question about 'Interac'. You sent this via email earlier. I replied but my email was not delivered:
A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:
webmaster@[...].com
all hosts for '[...].com' have been failing for a long time (and retry time not reached)
Which might also be a reason for security checks failing.
So again, you'll have to sort this out with your bank. This is outside the control of my payment provider or me.