1. REST API (which is used for paid lising and for paid membership, but no recurring)
2. CLASSIC API (which is used for recurring). Only classic api works with recurring and that is why we had to add both, even if it confuses clients a lot.
If you can’t make membership recurring work (i assume it is recurring), it means you didn’t set-up the PayPal classic API correctly or there are some restrictions in your PayPal settings. I would need to know exactly what message you get from paypal to see if I can help.