If you are using the W3 Total Cache plugin on your site then do the following to make it work with Simple Membership Plugin.
- Go to the “Advanced Rules” menu from WP Rocket Plugin’s admin menu.
- Scroll down to the “Never Cache Cookies” section.
- Add the following line in that field. See the screenshot below for reference.
swpm_in_use

Additionally, add the URL of your membership login page to the “Never Cache URL(s) field. So a cached login page is not shown to the visitors.