Connection to cluster3.eu.messagelabs.com Issue

Hi, 

One of our mailservers is currently unable to connect to cluster3.eu.messagelabs.com which prevents our cleints from sending emails to their partners and other clients.

Could you please review and whitelist 195.154.78.56

1i8O5D-001MF4-Un: H=cluster3.eu.messagelabs.com [85.158.142.99]: SMTP error from remote mail server after initial connection: 501 Connection rejected by policy [7.7] 22428, please visit www.messagelabs.com/support for more details about this error message.Connection to cluster3.eu.messagelabs.com

I have checked the blacklist and could not find any entries for that IP.

I'd appreciate a quick response and solution.