Forticlient loses EMS Connection

I am looking for possible solutions why my users are losing connection with the EMS server outside our network. The EMS server states unreachable on the forticlient at random times and loses the users credentials, also they are unable to reconnect to the EMS until they reconnect to our network internally. I work at a Police Department so my users need constant connection to VPN. What would cause the loss of connection to the EMS and they have to reconnect by coming back to the PD to connect to the internal network. Where should I start looking?