Cannot add Network-Server on first login

Hi, I am setting up the lora server for the first time using your documentation. I am using Ubuntu 16.04 OS. On server every service and process is running and I can login on web page also as admin. But while registering te Network-Server I am receiving this error

Error rpc error: code = Unavailable desc = all SubConns are in TransientFailure (code: 2)

I have been through with your other solution mentioned related to this problem but nothing works. Please let me know if you need more information from my side to help me out with this problem.

UPDATE: Problem solved, I figured it out.