Outbound Mail blocked due to Blacklisted Server

Outbound Mail blocked due to Blacklisted Server

Hello, I am getting email bounce back from due to the server being blacklisted. Can you please investigate and resolve.

admins@dnswl.org INVALID_ADDRESS, ERROR_CODE :554, ERROR_CODE :5.7.1 Service unavailable; Client host [165.254.167.163] blocked using ix.dnsbl.manitu.net; Your e-mail service was detected by mail.ixlab.de (NiX Spam) as spamming at Sun, 27 Dec 2015 22:20:27 +0100.

Thank You
Chris