Thank you all for your answers.
The clients appeared in the agent managed panes
The Problem was resolved in the following manner:
1. Restart the OpsMgr Config Service and OpsMgr Health Service in the SCE Server
2. Restart the OpsMgr Health Service on the client.
=> Nothing happened. I waited a couple of minutes and the Event Log Errors reappeared.
3. I tried to repair the Agent installation from the SCE Console.
=> But still no improvements.
4. I uninstalled the Agent from the Client and after one Client reboot I reinstall the Agent.
=> :-) Now the Agent is reporting and the status is monitored.
I tried to reinstall the Agent in the first place but without any luck.
I think the problem was the SCE Server.
Thanks
Dominik
Fuente: http://social.techne...63-72739c96bb67