Membership 2 communicating with PayPal

I need help with Membership 2 and PayPal... it seems to be acting up all of a sudden. Payments are failing.

Please see this thread in the support forum...

https://premium.wpmudev.org/forums/topic/redirect-problem-after-login

There were some other issues with members login. I know that James (support tech) had made some changes to the PayPal Config. I think sandbox mode was used by him to test somethings.
It looks like the regular settings for new subscribers are not correct.