Hello,
Will you check if your site is sending emails correctly? You can test this by installing the Check Email plugin:
https://wordpress.org/plugins/check-email/
And then send a test email from your WP > Tools > Check Email menu item.
Does the test email go through? If it does not, you will need to contact your host to let them know about this issue, or install an SMTP plugin to send your emails. If the test email does go through, I would just need to see a screenshot of your form's Settings > Emails tab. At that point, it would be best to create a topic in our help desk:
https://formidablepro.com/help-topics/