Problem with agent installed not reporting

Hi,

We have a DLP solution 14.5 (with 150 agents installed on the endpoint), but we have a problem with one of them, we installed the agent, and when we check the services of DLP  it's running, but we have not the agent reporting on the enforce (i mean, the machine is not displayed on the agent Overview (whether it's in reporting or not reporting), no trace of the machine.  How can we resolve this. Thank you

Best regards