Troubles with IP Reputation

Hi,

We are a ISP in Poland and got a complain from one of our customers in the last days. We received a Message that one of our IP is blacklisted somewhere at symantec.

If we go to the https://ipremoval.sms.symantec.com/ and check the IP We get the feedback that the IP don't have a bad reputation.

Can you check IP 51.75.62.100 for me or give me an information where it can be delisted?

Thank you for your supprt.

Krzysztof