I am trying to set up Membership so that once a user pays

Hi

I am trying to set up Membership so that once a user pays a subscription, they get added to one of my MailChimp mailing lists.

I've followed the instructions on the documentation but that didnt work and I also tried following the instructions on:

https://premium.wpmudev.org/forums/topic/pings-to-mailchimp#post-352778

and

https://premium.wpmudev.org/forums/topic/remote-ping-setup-with-mailchimp-not-working

Help please?