SMTP Status and Reply codes
This article gives you a list of SMTPSimple Mail Transport Protocol - An internet standard used for email transmission across IP networks. status codes and SMTP reply codes that can help you troubleshoot email issues within Kerio Connect.
These codes are present in Mail log and Debug log. Right-click in the Debug log window and select Messages > SMTP Client.
Below is a list of the most common codes that appear in the logs.
SMTP status codes
- 2.0.0 – Email has been delivered to the Inbox.
- 2.1.5 – Email has been delivered and moved to another folder due to a filtering rule.
- 4.1.1 – Email address does not exist.
- 4.4.1 – No answer from host or connection lost.
- 5.1.7 – Senders email address was incorrect or has bad syntax.
SMTP Reply Codes
- 220 – Server ready.
- 250 – Request mail action ok.
- 450 – Requested mail action not taken, mailbox unavailable.
- 451 – Request action aborted.
- 500 – Syntax error, command not recognized.
- 550 – Requested mail action not taken, mailbox unavailable.
- 554 – Transaction failed.
The below links show all status codes and what they represent.