WordPress has an option that allows anyone to go to WordPress’s registration page and create a WP user account. This WordPress feature can open your site up for spam user registration.
If you are getting a lot of spam WP user registration and you are not sure where it is coming from then this option is likely the cause for it.
You can find this settings option in the General WordPress settings menu of your site.
Settings -> General -> Membership
Our Simple Membership plugin DOES NOT need that option to be enabled.
So you should keep the “Anyone can register” checkbox unchecked.
The option mentioned here is not required by the Simple membership plugin because all user registrations for this plugin occur on the registration page created by our plugin. It’s possible that you or another plugin had enabled this option in the past when using a different plugin that required it. If you need this option due to another plugin, it is recommended that you use a captcha for the standard registration form.