Error while adding network server on docker


I am running the chirpstack on docker. I was able to create entire stack and login but while adding network server as chirpstack-network-server:8000, I am getting an error

chirpstack-application-server_1 | time=“2020-02-12T11:24:17Z” level=warning msg=“creating insecure network-server client” server=“chirpstack-network-server:8000”
chirpstack-application-server_1 | time=“2020-02-12T11:24:20Z” level=warning msg=“grpc: failed dns A record lookup due to lookup chirpstack-network-server on dial udp operation was canceled.\n”
chirpstack-application-server_1 | time=“2020-02-12T11:24:20Z” level=error msg=“finished unary call with code Unknown” ctx_id=6bd94e3c-4a22-485b-a87d-bea02685969e error=“rpc error: code = Unknown desc = context deadline exceeded” grpc.code=Unknown grpc.method=Create grpc.service=api.NetworkServerService grpc.start_time=“2020-02-12T11:24:17Z” grpc.time_ms=3391.054 peer.address=“” span.kind=server system=grpc