Did you define merchant key and ID inside the "currency and payments system" at system, reseller or manager level? Can you provide us a video of the error in order to understand better when you have the error 400?
there should be an additional field for passphrase as per payfast with their new security update
we are using the passphrase as we have our primary accounting server for our business so we needed the extra security
i will turn off passphrase for now
I'll informed our developers if they can add "passphrase" to Payfast settings under HSNM
When developers will add the passphrase under HSNM, can I contact you in order to enable passphrase on your account and make a test?