# rpc error: code = Unimplemented desc = method SayHello not implemented

- **ID:** `go/grpc-unimplemented-service-method`
- **Domain:** go
- **Category:** module_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The gRPC server does not have a handler registered for the invoked RPC method, possibly due to missing registration or incorrect service name.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 1.21 | active | — | — |
| 1.22 | active | — | — |

## Workarounds

1. **Ensure the server registers the service with the correct generated code.** (95% success)
   ```
   grpcServer := grpc.NewServer()
pb.RegisterGreeterServer(grpcServer, &myGreeterServer{})
   ```
2. **Verify the proto file and regenerate stubs if method was added recently.** (90% success)
   ```
   protoc --go_out=. --go-grpc_out=. *.proto
   ```

## Dead Ends

- **Restarting the server without changing code.** — The handler is still missing; restart doesn't add it. (100% fail)
- **Checking client method name only, ignoring server registration.** — The server must register the method; client alone can't fix it. (90% fail)