WP Mail SMTP fixes your email deliverability by reconfiguring WordPress to use a proper SMTP provider when sending emails.
SMTP (Simple Mail Transfer Protocol) is an industry standard for sending emails. Proper SMTP configuration helps increase email deliverability by using authentication.
Popular email clients like Gmail, Yahoo, Office 365, and Zoho are in a constant battle with email spammers. One of the things they look at is if an email is originating from the location it claims to be originating from.
If the proper authentication isn’t there, then emails either go in the SPAM folder or worst, don’t get delivered at all.
This is a problem for a lot of WordPress sites because by default, WordPress uses the PHP mail function to send emails generated by WordPress or any contact form.