diff --git a/observer_agent/grpc_comm/comm_server.cpp b/observer_agent/grpc_comm/comm_server.cpp
index 10aad3ebc24f9415804e4beb27d5a48bf3af4fb1..68686dec6fb901cd23f3f3d33d066dc07bef7f06 100644
--- a/observer_agent/grpc_comm/comm_server.cpp
+++ b/observer_agent/grpc_comm/comm_server.cpp
@@ -39,7 +39,11 @@ class PubSubServiceImpl final : public SubManager::Service {
     // ToDo: add extra check or feature code
     Message msg;
     msg.set_text("topic: " + std::to_string(cli_topic) + " Subscribe success!");
-    writer->Write(msg);
+
+    if (!writer->Write(msg)) {
+        std::cerr << "Failed to write the initial message" << std::endl;
+        return grpc::Status(grpc::StatusCode::INTERNAL, "Failed to write the message");
+    }
     
     // ToDo: set some condition to break loop
     while (1) {}
@@ -53,10 +57,14 @@ class PubSubServiceImpl final : public SubManager::Service {
 
     if (subscribers_.find(cli_topic) != subscribers_.end()) {
         for (auto& subscriber : subscribers_[cli_topic]) {
-	    Message msg;
-	    msg.set_text(cli_data);
-	    subscriber->Write(msg);
-	}
+	          Message msg;
+	          msg.set_text(cli_data);
+
+            if (!subscriber->Write(msg)) {
+                std::cerr << "Failed to write to a subscriber" << std::endl;
+            }
+	    
+	      }
     }
     return grpc::Status::OK;
   }