diff --git a/internal/proxy/impl.go b/internal/proxy/impl.go
index ab773aede3..e82bed113d 100644
--- a/internal/proxy/impl.go
+++ b/internal/proxy/impl.go
@@ -1562,7 +1562,8 @@ func (node *Proxy) Query(ctx context.Context, request *milvuspb.QueryRequest) (*
 		}, nil
 	}
 
-	err = errors.New("Not implemented because:" + err.Error())
+	errMsg := "Invalid expression!"
+	err = errors.New(errMsg)
 	return &milvuspb.QueryResults{
 		Status: &commonpb.Status{
 			ErrorCode: commonpb.ErrorCode_UnexpectedError,