docker/envoy connection error

[Grpc-gig]

why am i getting error in envoy grpc (
grpcurl -plaintext localhost:8000 describe pb.app

Failed to dial target host "localhost:8000": connection error: desc = "transport: error while dialing: dial tcp [::1]:8000: connect: connection refused"
)

[Grpc-gig]

here is my envoy file
`admin:
access_log_path: /tmp/admin_access.log
address:
socket_address: { address: 0.0.0.0, port_value: 9901 }

static_resources:
listeners:
- name: listener_0
address:
socket_address: { address: 0.0.0.0, port_value: 8000 }
filter_chains:
- filters:
- name: envoy.http_connection_manager
config:
codec_type: AUTO
stat_prefix: ingress_http
route_config:
name: local_route
virtual_hosts:
- name: local_service
domains: [""]
cors:
allow_origin_string_match:
- safe_regex:
google_re2: {}
regex: "."
allow_methods: GET, PUT, DELETE, POST, OPTIONS
allow_headers: >-
authorization,
keep-alive,
user-agent,
cache-control,
content-type,
x-accept-content-transfer-encoding,
x-accept-response-streaming,
x-user-agent,
x-grpc-web,
grpc-timeout
expose_headers: custom-header-1,grpc-status,grpc-message
max_age: "1728000"
routes:
- match:
prefix: "/"
route:
cluster: api_interface
http_filters:
- name: envoy.cors
- name: envoy.grpc_web
- name: envoy.router

clusters:
- name: api_interface
connect_timeout: 0.25s
type: logical_dns
lb_policy: round_robin
http2_protocol_options: {}
load_assignment:
cluster_name: api_interface
endpoints:
- lb_endpoints:
- endpoint:
address:
socket_address:
address: localhost
port_value: 8090
`