There are 2 common problems when the email does not received.
Your emails are seen as Spam
Spoof emails are similar to spam emails. Spoofing means that someone else is faking the sender’s address. And any emails that are suspected of spoofing rarely even make it to an inbox.
Your hosting company doesn’t use the PHP Mail function
If your web host doesn’t support the PHP mail function, (which is very common these days), that could be the reason the contact form isn’t sending emails. The WordPress wp_mail() function relies on PHP mail to send emails from your site, including emails generated by contact form plugins, but many hosts disable it.
Even if your host does allow your site to use PHP mail, it’s a pretty lousy way to send emails. PHP mail is extremely basic, and WordPress can’t add any authentication information to the emails that it generates. That means your Contact Form 7 emails can look like generic spam messages.
This is why we recommend using an SMTP plugin to send emails from WordPress instead of using the default PHP mail function by itself. Find the SMTP plugin in the official WordPress directory – https://wordpress.org/plugins/search/smtp/