Email not delivered to downstream MTA (Email Security.cloud)

Products

• Data Loss Prevention Network Prevent for Email
• Data Loss Prevention

Issue/Introduction

When making telnet to port 25 to the email prevent server from upstream MTA getting the below error:
[Telnet] Fatal: Forwarding agent unavailable. Closing Connection

 

Error messages found in SMTP logs of detection server:

[SEVERE] (SMTP_CONNECTION.5203) Forward connection error (tid=3f cid=b15a4fed-e11e-4e52-a6c9-8aae25******* mta=cluster4.eu.messagelabs.com reason=Connection refused: no further information)
[SEVERE] (SMTP_CONNECTION.5210) All forward hosts unavailable (tid=3f cid=<> reason=No available forward hosts)

Resolution

Try clearing DNS cache - often it resolves the issue.

NOTE:

If this doesn't help - contact Security.cloud (aka Messagelabs) support to see if the issue is communication related.