Error #7, TOKEN is missing

Hi there,
We have recently got approved Reference Transactions on Paypal and I’m not sure if that’s changed something but users are getting below message when trying to make a payment via Paypal Pro Form (using paypal)

Error #7. Field format error: TOKEN is missing.

We have token added in S2member settings > PayPal PDT Identity Token.
Why it says missing if the token is added there?

Did anyone came across this issue? Any cure for that?

Many thanks,
Adam