Let’s say you have 5 different site, all based on WordPress’s multisite. What if a user get registered in one of your 5 site, and he want to get access all over 5 sites.
Problem?
If this is your problem, you can resolve this problem with one click. Just Network activate this plugin, and a user will get access to all of your site.
If you have any issue, open a ticket in the support section. I will resolve your issue as soon as possible.