I have attempted to get this issue resolved in a response to a previous post and been unsuccessful. Hopefully a new topic thread will help developers answer this question and as well as help others looking for a similar fix.
I was recently upgraded to Membership Pro 2 and have since been trying to mimic settings I had in the previous Membership Plugin (If it ain't broke, don't fix it -- what I had worked perfectly fine and I wish WPMU Developers would have given users to option to keep either the Membership or Install the Membership2. But alas).
I was informed that there IS a way to activate Invite Codes to help restrict registration on websites (Membership --> Add-Ons --> Invite and then an invite code tab will appear under Membership 2 for those looking).
However, this add-on IS NOT WORKING. I can create an invite code (say, "InviteMe!") but when I try to set the option for "Invitation can be applied to these Memberships" no matter which toggle box I check (any or the membership) after clicking save changes it AUTOMATICALLY REVERTS BACK TO "ANY".
I have tried simplifying my membership options to only one membership -- thinking that then the membership code field would be applied to the registration page form, but this doesn't work either.
As a result of this issue, I am losing students and have had to put my site on maintenance mode in order to prevent non-students from registering for the website and gaining access to the information.
Please provide a fix ASAP as I have seen this question asked multiple times within the forums in some variation or another.
(please see previous thread for reference: https://premium.wpmudev.org/forums/topic/access-code-subscriptions-in-membership2#post-894534)