Sending E-mails
MAIL_URL: The server reads from the MAIL_URL environment variable to determine how to send mail. The MAIL_URL should reference an SMTP server and use the form:
smtp://USERNAME:PASSWORD@HOST:PORT
or
smtps://USERNAME:PASSWORD@HOST:PORT
The smtps:// form (the s is for “secure”) should be used if the mail server requires TLS/SSL (and does not use STARTTLS) and is most common on port 465. Connections which start unencrypted prior to being upgraded to TLS/SSL (using STARTTLS) typically use port 587 (and sometimes 25) and should use smtp://. For more information see the Nodemailer docs