Within the User Interface (UI) of Advanced Threat Protection (ATP) Platform 2.0, Periodically, the status of the Symantec Endpoint Protection Manager (SEPM) controller connection changes from "Healthy" to "Authentication error".
Within the ATP UI, on the Settings> Global Settings, the connection status for SEPM Controller sometime changes to "Authentication error".
Delete and re-enter the credentials for connecting to the SEPM in the SEPM Controller settings.