There’s a problem with either the DigitalOcean firewalls or something similar. Can’t send emails using both Postfix and Sendmail. I’ve put no firewalls in place. All ports open, but still can’t send. Please fix ASAP.

Steps to reproduce the case:

1. Create a Debian-9-64bit 1GB droplet.
2. Update system using apt-get update && apt-get dist-upgrade
3. Now install Postfix using apt-get install postfix postfix-mysql postfix-doc openssl getmail4 rkhunter binutils dovecot-imapd dovecot-pop3d dovecot-mysql dovecot-sieve dovecot-lmtpd mailutils
4. Send a test mail, echo “This is the body of the email” | mail -s “This is the subject line” youremailaddress Now, the mail never gets sent. Please look into this issue.