Payfast Signature Error

I have integrated my PayFast account into InvoicePlane V1.5.9 and i get the following error after pressing paynow in invoiceplane.

The supplied variables are not according to specification:

signature : Generated signature does not match submitted signature

Please if anyone has some advise on what i can look at on this as everything else is exactly how i want it but this hickup is the last item i need to fix.

A post was merged into an existing topic: PayFast Payment Gateway