by EverPress on WordPress.org
Verifies your Users email addresses and blocks them from register to your site.
Redirects all email sent through wordpress to the user currently logged in or the site administrator.
Stryker SMTP sends all WordPress emails through an SMTP server of your choice. Configure SMTP credentials from the wp-admin settings page.
This plugin is useful for disabling user-wise mail. You need to drag and drop the user and save it then this will work automatically.