Hi,
This seems to be a known issue with 12.1. It seems to have been fixed in 12.1.RU 1
Client shows as offline within SEPM even though it is functional on the endpoint
Fix ID: 2436933
Symptom: Within the SEPM console, the client status is showing as "offline". On the endpoint, the SEP client is functioning as expected.
Solution: Resolved by changes to the client recognition logic. The "hardware ID" and "known client ID" values are now handled differently within SEPM to ensure that clients are correctly recognized by the Manager.
http://www.symantec.com/business/support/index?page=content&id=TECH174565