Is there a static list of IP addresses, which must be open on proxy for clients connected to ICDm?
Proxy or Firewall blocks ICDm access.
Broadcom recommends specifying ICDm required servers via DNS name (fully qualified domain name), not via one or more IP addresses, as IP addresses, resolved from the required URLs, are not static and IP address information is changed periodically. Use of static IP addresses for accessing the Integrated Cyber Defense Manager (ICDm) cloud console is not supported or recommended.
For more information on URLs that allow SEP and SES to connect to Symantec servers, please, check the following guide: