What Does the Error Look Like?#
I ran into this error while trying to send emails through a custom app I built. The emails were going through smtp.mailchannels.net, which is a cPanel subservice. Luckily, customer support was available to help, but if you’re scratching your head over this error, keep reading for the fix.
If you’re sending email through a client app like Roundcube:
SMTP Error (550): Failed to add recipient “user@external.com” (Outgoing mail from “internal.com” has been suspended.).
If you’re using Laravel:
Expected response code “250/251/252” but got code “550”, with message “550 Outgoing mail from “internal.com” has been suspended.”
What Does This Error Mean?#
This usually happens when your hosting provider blocks or suspends outgoing emails from your domain (e.g., internal.com). Common reasons include:
- Spam detection triggered
- Email sending quota exceeded
- Account-related issues
- Missing domain verification records (SPF, DKIM, DMARC)
- Policy violations detected
How to Fix It#
First things first — contact your hosting provider. They’re the only ones who can lift the suspension since it’s related to email authentication on cPanel’s webmail.
Once your provider resolves the issue, make sure to check:
- Your daily webmail sending limit
- Your hourly email sending quota
To avoid hitting these limits again, consider adding delays using functions like sleep() or implementing a queue system to space out your email requests over time.
Alternative Email Platforms#
If you keep running into issues, you might want to consider switching to a dedicated email service:
Hope this helped! If you found this article useful, feel free to share it with others who might be dealing with the same issue.
