Failed to communicate agent

Failed to communicate agent

Hi,
 
With the ManageEngine agent, I cannot get the Service Desk server to Scan the machine. I get "Failed To Communicate Agent" , even though the ManageEngine service on the PC  is running and listening on port 9000. I can also telnet to this port on the affected PC.
Agent software is up-to-date also.
 
Anyone know how to solve this issue ?
 
Regards

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