Build the best contact forms in your WordPress website.
The plugin uses the settings specified into the WordPress website to deliver the emails. If the emails aren't being reaching to their destination check in this article how to proceed.
If the emails are not being sent from a WordPress plugin then try first using a "from" email address that belongs to your website domain, this is the most common restriction applied in most hosting services.
If that doesn't work please check if your hosting service requires some specific configuration to send emails from PHP/WordPress websites. The plugins use the settings specified into the WordPress website to deliver the emails, if your hosting has some specific requirements like a fixed "from" address or a custom "SMTP" server those settings must be configured into the WordPress website.
If your hosting service tells you to send the emails via a SMTP server then you can install an additional plugin to setup the SMTP configuration.
Other useful steps may be to install an email log plugin to check exactly which emails have been "sent" from the WordPress website.
Finally, if you reach to an end point with your hosting email service you can opt for using a third party email delivery service like Gmail (requires to setup a SMTP plugin) or the SendGrid email service.
Feedback about these features will be welcome, feel free to open a support ticket for any question.