We'll create fresh WordPress site with Wp Single Login installed. You have 20 minutes to test the plugin after that site we'll be deleted.
This plugin will automatically logout the already logged in user when a user with the same login details tries to login from different browser or different computer. This plugin needs zero configuration to run. Just install it if you want single login functionality on your site.
This plugin uses wordpress Heartbit API which was implemented in version 3.6 in order to logout users in real time.