After upgrading to version 21, some Automic Agents from time to time become unreachable from the Automation Engine side and are displayed as "Stopped".
As a result, the Job processing stops causing a lot of production issues.
In AE logs we can see some errors such as:
20211216/103941.771 - U00005002 No hosts could be found for the AgentGroup 'OVBINT_S.SSAS.AZ.HOSTG'. 20211216/104023.002 - U00005011 AgentGroup 'MSC.SQLORA.HOSTG' (host attribute type 'SQL'): the given host attribute type 'WINDOWS' is incorrect. 20211216/104023.007 - U00005011 AgentGroup 'OVBINT_S.INFA_UNX.HOSTG' (host attribute type 'UNIX'): the given host attribute type 'WINDOWS' is incorrect.
Release : 21.0
Component : AUTOMATION ENGINE
Defect in Automation Engine side, most likely in the JCP, but issue cannot be reproduced at will for the moment.
Restart all Agents seen as Inactive via the Service Manager dialog, agents will be seen as Active by the Automation Engine after that and processing will resume.
Update to a fix version listed below or a newer version if available.
Component(s): Automation Engine
Automation.Engine 21.0.2HF1 - Available
Automation.Engine 21.0.3 - Available
If you experience this issue, please open a case with support and enable the trace tcpip=4 on the JCPs and provide the logs of the Agents affected and the JCP logs and traces.