Why you are seeing this error

If Mailbird shows an outgoing connection error such as Connection refused - OB115, Connection refused - OB119, is blacklisted, or connection refused from <IP>, the problem is usually not Mailbird itself. It usually means the outgoing mail server has rejected the connection because the sending IP address has been flagged by an anti-spam or reputation system.

Common error messages

• Connection refused - OB115.
• Connection refused - OB119.
• is blacklisted
• blacklisted in Abusix Mail Intelligence
• connection refused from

What to do

1. Check whether the message mentions a blacklist provider such as Abusix or Cloudmark.
2. Contact your email provider, hosting company, or IT admin and ask whether the outgoing server or sender IP has been blocked.
3. If the message contains a removal URL or postmaster address, follow that provider guidance.
4. Verify that you are using the correct SMTP server, port, and encryption settings for your provider.
5. If you are sending through a company or hosted mail server, ask the server administrator to investigate the IP reputation and outbound relay policy.

Important note

This kind of rejection is usually caused by the mail server or sender reputation, not by Mailbird. Mailbird is only showing the server response it received.