Cloudmark Sender Intelligence (CSI) is a service that provides data about the reputations of message-sending servers to messaging service providers. The data indicates which servers usually send spam and which ones usually send legitimate messages. Data about some servers may be ambiguous.
Different service providers have different policies about what to do with CSI's data, especially about how to interpret reputations that are ambigous. Cloudmark is not a messaging service provider and does not block your messages, but your service provider may choose to do so.
If your service provider has indicated that your message are being blocked because of data from CSI, complete the CSI remediation form to resolve the problem.