diff --git a/include/rest_rpc/rpc_client.hpp b/include/rest_rpc/rpc_client.hpp
index 65b626d..2ea5de6 100644
--- a/include/rest_rpc/rpc_client.hpp
+++ b/include/rest_rpc/rpc_client.hpp
@@ -41,7 +41,8 @@ class req_result {
 
   void as() {
     if (has_error(data_)) {
-      throw std::logic_error(get_error_msg(data_));
+      std::string err_msg = data_.empty() ? data_ : get_error_msg(data_);
+      throw std::logic_error(err_msg);
     }
   }