Two scanner servers recently showed as offline. They continued top be offline after restarting the Symantec Protection Engine service.
A look at the cafagent.log, located in "C:\Program Files\Symantec\Common Agent Framework\Log", showed the following series of events (both servers)
2022-12-20 18:41:06 | adapter.SPEAdapter | Error | 9000 : 92 : adapter::SPEAdapter::SendCommandToAgent:971 | Failed to establish connection with 127.0.0.1:9002
2022-12-20 18:41:06 | adapter.SPEAdapter | Error | 9000 : 92 : adapter::SPEAdapter::fetchTechStatus:1194 | SPEAdapter failed to fetch technology status from the agent.
2022-12-20 18:41:09 | cafservice.CAFAgentInfoManager | Error | 9000 : 856 : caf::CAFAgentInfoManager::SendAgentInfo::<lambda_fa0eb50d06b4ccf3a1403c77e293d9e6>::operator ():461 | Updating agent information/technology status failed.
2022-12-20 18:41:09 | cafservice.CAFAgentInfoManager | Error | 9000 : 856 : caf::CAFAgentInfoManager::SendAgentInfo::<lambda_fa0eb50d06b4ccf3a1403c77e293d9e6>::operator ():462 | The error code is: 20
2022-12-20 18:41:09 | cafservice.CAFAgentInfoManager | Error | 9000 : 856 : caf::CAFAgentInfoManager::SendAgentInfo::<lambda_fa0eb50d06b4ccf3a1403c77e293d9e6>::operator ():463 | Error message: HttpTransportNetworkError
2022-12-20 18:41:09 | cafservice.CAFAgentInfoManager | Error | 9000 : 856 : caf::CAFAgentInfoManager::SendAgentInfo::<lambda_fa0eb50d06b4ccf3a1403c77e293d9e6>::operator ():464 | Error details:{"0":{"0":"ProxyModeManual (1)","1":"EpmpClientErrorCodes: HttpTransportNetworkError (20)","2":{"0":"windows","1":8,"2":"Not enough storage is available to process this command.\r\n"}},"1":{"0":"ProxyModeManual (1)","1":"EpmpClientErrorCodes: HttpTransportNetworkError (20)","2":{"0":"windows","1":8,"2":"Not enough storage is available to process this command.\r\n"}},"2":{"0":"ProxyModeManual (1)","1":"EpmpClientErrorCodes: HttpTransportNetworkError (20)","2":{"0":"windows","1":8,"2":"Not enough storage is available to process this command.\r\n"}},"3":{"0":"ProxyModeManual (1)","1":"EpmpClientErrorCodes: HttpTransportNetworkError (20)","2":{"0":"windows","1":8,"2":"Not enough storage is available to process this command.\r\n"}},"4":{"0":"ProxyModeManual (1)","1":"EpmpClientErrorCodes: HttpTransportNetworkError (20)","2":{"0":"windows","1":8,"2":"Not enough storage is available to process this command.\r\n"}},"5":{"0":"ProxyModeDisabled (16)","1":"EpmpClientErrorCodes: HttpTransportNetworkError (20)","2":{"0":"windows","1":8,"2":"Not enough storage is available to process this command.\r\n"}},"6":{"0":"ProxyModeAutoDetect (2)","1":"EpmpClientErrorCodes: HttpTransportNetworkError (20)","2":{"0":"windows","1":8,"2":"Not enough storage is available to process this command.\r\n"}},"7":{"0":"ProxyModeDefault (8)","1":"EpmpClientErrorCodes: HttpTransportNetworkError (20)","2":{"0":"windows","1":8,"2":"Not enough storage is available to process this command.\r\n"}}}
2022-12-20 18:41:09 | cafservice.CAFAgentInfoManager | Error | 9000 : 856 : caf::CAFAgentInfoManager::SendAgentInfo::<lambda_fa0eb50d06b4ccf3a1403c77e293d9e6>::operator ():493 | HTTP Transport error caused by some network problem, error message:HttpTransportNetworkError
Release : 8.2.2
The servers had recently been patched and had a pending reboot which often cause network related operations to fail or become unreliable.
Rebooting the servers corrected the problem.