Per Kimberly: I am starting a new thread. I am experiencing the same problem as discribed in this one: https://premium.wpmudev.org/forums/topic/membership-step-two-does-not-redirect-to-step-3-on-success.
I am running Membership 2.1.4 and finishing the gateway integration with authorize.net. Membership is set to Live and authorize.net is in test mode. After submitting the credit card information the page goes blank. Checking the admin information, the account was registered and the subscription completed with authorize.net. The admin email receives confirmation of the user registration from Wordpress and 3 emails from authorize.net confirming the payment (showing it was processed in test mode).
The thread referenced above says the fix is to set the "Registration completed page" option to the page you want the new user to see after registration. My setup does not have that option in Membership ->Options.
Any suggestions on why I dont have that option, or how I can fix the blank page?