You receive the following error when trying to modify an agent to change its agent group assignment:
"no user defined group exists"
DLP 15.X, 16.X
The agent group that was created does not have an agent configuration assigned to it.
If this has not resolved your issue, please see topic: Cannot select "Default Group" after moving DLP Agent out of Default Group
This topic is useful if you are unable to change agent groups in the enforce console when original group is 'default' or you are otherwise are having difficulty reassigning an agent group.
If the Agent groups do not show up in Change Group tasks, please review this article:
Agent groups defined by Endpoint servers do not show up in Change Group tasks