If you are using the WP Super Cache plugin on your site then do the following to make it work with Simple Membership Plugin.
- Go to your WP Super Cache plugin’s Advanced Settings menu.
- Check the “Don’t cache pages for known users” checkbox.
- Check the “Late init” checkbox.
- Save the settings.
You should exclude the membership login page from caching.
You should also set the cache garbage collection interval to a value that is less than 24 hours.