Many site owners have to deal with spam mail issues when using the default PHP mail function() of WordPress. Mail service may have restrictions: Sometimes emails are not delivered or sites exceed the limit on outgoing mail. Bit SMTP plugin allows to authenticate your mail service by configuring the SMTP servers of the desired mail service. SMTP is a protocol that makes your WordPress site's email delivery easier and more reliable. This feature allows you to send mail from your website to your recipients using your preferred mail server.