Hi... I suspect this may be the issue covered in KB51209 in the knowledge base.
Can i just copy all the client key and paste it into epo rsd folder?
Did the epo RSD and sensor share the same key?
Yes, you can copy the root.pem, key.pem, and sensor.pem files into the RSD Sensor install folder then cycle the RSD sensor service and that should get it communicating.