c# - The type or namespace name 'GroundTruth' does not exist in the namespace 'Osi3' (are you missing an assembly reference?)

Question

I tried building the .cs files from the .proto via grpc.. but the file contains many errors which i am unable to resolve.

.proto file is

syntax = "proto3";


import "osi_groundtruth.proto";

package osi3;
service Groundtruthdata {
  // rpc ProcessGroundTruth(trial) returns(Empty) {}
   rpc ProcessGroundTruth(GroundTruth) returns(Empty){}
   rpc SayHello (HelloRequest) returns (HelloReply) {}
}
//message trial{
//  GroundTruth gt = 1;
//}

message Empty {
  string result = 1;
}
// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

and the errors generated are C# code error log