diff --git a/td/telegram/AuthManager.cpp b/td/telegram/AuthManager.cpp
index e4d030481..2cc89fe07 100644
--- a/td/telegram/AuthManager.cpp
+++ b/td/telegram/AuthManager.cpp
@@ -690,7 +690,7 @@ void AuthManager::on_log_out_result(NetQueryPtr &result) {
     on_query_ok();
   }
 }
-void AuthManager::on_authorization_lost(const string &source) {
+void AuthManager::on_authorization_lost(string source) {
   LOG(WARNING) << "Lost authorization because of " << source;
   destroy_auth_keys();
 }
diff --git a/td/telegram/AuthManager.h b/td/telegram/AuthManager.h
index d8d58ab82..1580cffed 100644
--- a/td/telegram/AuthManager.h
+++ b/td/telegram/AuthManager.h
@@ -49,7 +49,7 @@ class AuthManager final : public NetActor {
 
   void on_update_login_token();
 
-  void on_authorization_lost(const string &source);
+  void on_authorization_lost(string source);
   void on_closing(bool destroy_flag);
 
   // can return nullptr if state isn't initialized yet