diff --git a/projects/loafer/ng-rpc/src/lib/client/RPCClient.ts b/projects/loafer/ng-rpc/src/lib/client/RPCClient.ts
index b46db31..2b26737 100644
--- a/projects/loafer/ng-rpc/src/lib/client/RPCClient.ts
+++ b/projects/loafer/ng-rpc/src/lib/client/RPCClient.ts
@@ -130,15 +130,15 @@ export abstract class RPCClient<T> {
     this._pendingRequests.delete(id);
     this._pendingRequestsCount--;
 
-    if (undefined !== result) {
-      reqState.subject.next(result);
-    } else if (undefined !== error) {
+    if (undefined !== error) {
       const rpcClientError: RPCClientError = {
         request: reqState.request,
         response: error,
       };
       console.error(rpcClientError);
       reqState.subject.error(rpcClientError);
+    } else {
+      reqState.subject.next(result);
     }
   }
 
diff --git a/projects/loafer/ng-rpc/src/lib/protocol/json/JSONRPCClientCodec.ts b/projects/loafer/ng-rpc/src/lib/protocol/json/JSONRPCClientCodec.ts
index 27d3980..a18971d 100644
--- a/projects/loafer/ng-rpc/src/lib/protocol/json/JSONRPCClientCodec.ts
+++ b/projects/loafer/ng-rpc/src/lib/protocol/json/JSONRPCClientCodec.ts
@@ -94,10 +94,10 @@ export class JSONRPCClientResponseCodec implements RPCClientResponseCodec {
   }
 
   public isNotification(): boolean {
-    if (undefined !== this.id() || undefined === this.result()) {
-      return false;
+    if (undefined === this.id() && undefined !== this.result()) {
+      return true;
     }
-    return true;
+    return false;
   }
 
   public notification(): RPCClientNotificationCodec | undefined {