It is possible that your emails are not getting delivered. There can be many reasons such as wrong server configurations to use the PHP mail() function or port blocked by the host.

Even sometimes, if the mail is sent through WordPress, it doesn't reach the customer's Inbox and goes to the spam box. As such, it is recommended to use SMTP when you are sending emails with Dynamic Email. SMTP uses proper authentication that results in high email deliverability.

To use SMTP, you can use the free WP SMTP plugin and use any SMTP mailing service such as SendGrid, Sendinblue, Mailgun, or Gmail SMTP.

Basically, you will need to create an account on the mailing service and get an API or credentials to later integrate it into WP SMTP plugin settings.

You can also launch the setup Wizard to easily set up the mailing service with the plugin.