The Cisco Technical Assistance Center (TAC) is critical for maintaining enterprise uptime. If your CUCM system suffers a database replication failure, a dropped subscriber node, or a core dial-peer issue, you rely on TAC to resolve it.When you open a case, TAC engineers run automated diagnostic scripts (such as Cisco Collaboration System Release validation tools) that instantly check the Smart Licensing registration status. If a crack or anomaly is detected: Support is immediately denied. Your smart account can be flagged for audit.