KojoTate

I am currently building a Membership Site for a Military Sorority. We want to regulate access to the account and eliminate the option to Create an Account and only have the option to sign in only. This way, my client can vet the potential members through their application process and manually create an account that the approved new member can log in to. The issue right now is when you go to login on to a membership page, the popup still has the option to create an account on it. Does anyone have a solution for this problem or some code that can get rid of all options to create an account on the site and have it as strictly a login option? They have already invested in the Membership add-on, so I would prefer to stay with it if it can be resolved. But, if there is not an option to solve this within the Squarespace Membership, then can anyone recommend an alternate service that I could link them to that would provide the same services?