501 Connection rejected by policy [7.7] 6207

Hello,

We had emails from one of our servers to your network failing with the below errors, but IP is not listed in any of the major spam databases and while testing at http://ipremoval.sms.symantec.com/ it says not listed as well. Can you please provide a solution?

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H=cluster1.ap.messagelabs.com [117.120.16.147]: SMTP error from remote mail server after initial connection: 501 Connection rejected by policy [7.7] 6211, please visit www.messagelabs.com/support for more details about this error message.

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 The IP address you submitted, x.x.x.x, does not have a negative reputation and therefore cannot be submitted for investigation.