Message from Spamhaus : " Your IP address (128.204.223.47) is either exhibiting suspect behavior, is misconfigured, or has a poor sending reputation.
As a result, the IP is listed in the CSS Blocklist (CSS)
Click on Show Details to see if you can request a delisting from this blocklist. This will also display any further information we have relating to this listing.
What is CSS?
The Spamhaus CSS is a component of the Spamhuas Blocklist (SBL).
The CSS list is an automatically produced dataset of IP addresses that are involved in sending low-reputation email. CSS mostly targets static spam emitters but may also include other senders that display a risk to our users, such as compromised hosts. CSS lists both IPv4 addresses (/32) and IPv6 addresses (/64 or larger). CSS listings are influenced by:
Email showing indications of unsolicited nature;
Having poor list-hygiene;
Sending out bad email due to a compromise, insecure installation or misconfigured server;
Other indicators of low reputation or abuse.
CSS listings are based on a wide range of inputs and are always the result of multiple events and heuristics."