When your WordPress website runs on a N99panel VPS, in order to send email from WordPress forms etc., we advise you to use the WP Mail SMTP Plugin. Also you would need to have a valid email ID for which you have the SMTP access.
In order to configure WP Mail SMTP, please refer to the following documentation : https://wpmailsmtp.com/docs/how-to-set-up-the-other-smtp-mailer-in-wp-mail-smtp/ . Also once you have configured WP SMTP, you can send a test email to verify whether it is working or not. To test the same, the WordPress menu hierarchy is WordPress Dashboard >> WP Mail SMTP >> Tools >> Email Test.