Why is SMTP blocked?
SMTP port 25 is blocked on all Rcs.iss for new accounts to prevent spam and other abuses of our platform.
Dedicated email deliverability platforms are better at handling deliverability factors like IP reputation. To send mail from Rcs.is, we recommend using SendGrid:
SendGrid delivers your transactional and marketing emails through the world’s largest cloud-based email delivery platform.
marketplace.Rcs.is
Even on older accounts where SMTP may be available, we strongly recommend against running your own mail server in favor of using a dedicated email deliverability platform.
