Using SendGrid For Mailing

By default, the wp_mail() function handles all the mail requests inside of WordPress, similar to PHP’s mail function. However, since all standard outgoing SMTP ports are blocked by Google’s Compute Engine by default, SendGrid is used to handle emails.

To integrate SendGrid, the WP Mail SMTP plugin is used. When installed, simply use the by SendGrid provided API Key to connect WordPress to their service. The WP Mail SMTP plugin reconfigures the default wp_mail() functionality to SendGrid entirely, so this should solve the issues right away.