gRPC server ( has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource)

• Started the gRPC server() which is running on the 6565 port
• Started envoy server with below configuration

static_resources: listeners: - address: socket_address: address: 0.0.0.0 port_value: 8080 filter_chains: - filters: - name: envoy.filters.network.http_connection_manager typed_config: "@type": codec_type: AUTO stat_prefix: ingress_http access_log: - name: envoy.access_loggers.stdout typed_config: "@type": route_config: name: local_route virtual_hosts: - name: backend domains: - "*" routes: - match: prefix: "/" grpc: {} route: cluster: backend_grpc_service cors: allow_origin_string_match: - prefix: "*" - safe_regex: google_re2: {} regex: \* allow_methods: GET, PUT, DELETE, POST, OPTIONS allow_headers: keep-alive,user-agent,cache-control,content-type,content-transfer-encoding,x-accept-content-transfer-encoding,x-accept-response-streaming,x-user-agent,x-grpc-web,grpc-timeout,Access-Control-Allow-Origin max_age: "1728000" expose_headers: grpc-status,grpc-message http_filters: - name: envoy.grpc_web typed_config: "@type": - name: envoy.cors typed_config: "@type": - name: envoy.filters.http.router typed_config: "@type": clusters: - name: backend_grpc_service type: STRICT_DNS lb_policy: ROUND_ROBIN typed_extension_protocol_options: envoy.extensions.upstreams.http.v3.HttpProtocolOptions: "@type": explicit_http_config: http2_protocol_options: {} load_assignment: cluster_name: backend_grpc_service endpoints: - lb_endpoints: - endpoint: address: socket_address: address: localhost port_value: 6565

• Started the grpcWebClient ()
• Opened the browser upon performing client operations I get below errors

Allowing all origins with below snippet, But it throws an error with Access-Control-Allow-Origin not present

allow_origin_string_match: - prefix: "*"

Browser console log

localhost/:1 Access to XMLHttpRequest at ' from origin ' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
bundle.js:1136 Uncaught TypeError: Cannot read properties of null (reading 'getResult')

3 Related questions 1 Envoy proxy for GRPC service mesh 11 Why is envoy proxy required for grpc-web? 2 How do I set up an envoy proxy in Minikube for a gRPC service? Related questions 1 Envoy proxy for GRPC service mesh 11 Why is envoy proxy required for grpc-web? 2 How do I set up an envoy proxy in Minikube for a gRPC service? 2 SSL error ERR_CERT_AUTHORITY_INVALID when using Envoy proxy in front of gRPC service 0 How to call grpc-web proxy from a NodeJS server 0 Error connecting Node.js web client to Java gRPC server 3 GRPC-Web connectivity issue in TLS 1 GRPC Java load-balancing - start method is not being called from NameResolver 1 Simple gRPC envoy configuration 2 Envoy Proxy with GRPC Server Streaming throwing UNAVAILABLE: upstream request timeout Load 7 more related questions Show fewer related questions Sorted by: Reset to default

Know someone who can answer? Share a link to this question via email, Twitter, or Facebook.

Your Answer

Sign up or log in

Sign up using Google Sign up using Facebook Sign up using Email and Password Submit

Post as a guest

Post Your Answer Discard

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.