1. Contact Form 7 plugin may not work if you have "maintenance mode" or any "website is coming soon" plugins enabled.
2. It doesn't work on localhost.
3. Some people reported issues on the following servers:
   • Bluehost
   • Cliche Webhosting
   • GoDaddy
   This can be fixed by the server administrators.
4. Other than that Contact Form 7 is successfully used by over 5,000,000 people and it's up to the hosting company to make it work out of the box. If it doesn't work please contact the server administrator and ask them to fix that (plugin support, theme support and WordPress support will not help you if this is a server issue).

Debugging it by yourself (follow the steps until it works)

1. Make sure that the form is configured correctly in Contact → Contact Forms → (your form) → Mail.
2. Activate the default WordPress theme and check if the plugin works.
3. Deactivate other plugins and check if it works.
4. Put <?php wp_mail( get_option( 'admin_email' ), 'subject', 'message' ); ?> in functions.php at the very top, reload your website and check if you received any email.
   • If you won't receive an email then it's an indicator that the source of the problem probably lies somewhere in the SMTP configuration of the server. The server must support mail() (PHP) and wp_mail() (WordPress) functions.
   • If you received an email this way (but you still don't receive any emails using the plugin) then it's probable that the server rejected the plugin's custom headers. The plugin allows sending emails on behalf of another domain which may be prohibited by the server and thus such email won't be sent.
5. Contact the server administrator.

Additional information

1. This plugin is supposed to work right after you install it. You don't have to configure absolutely anything. It will send emails to the email address of the administrator account of your WordPress website by default.
2. If the hosting company tells you that it's not the issue on their end, please don't believe them. Everyone who has had this issue so far had it because of the server's configuration and it was eventually resolved by the hosting company.
3. Please contact us only if it does work with the default theme but doesn't work with one of our themes.
4. This issue happens to roughly 1 person in 100.