diff --git a/td/telegram/Client.cpp b/td/telegram/Client.cpp
index c4a50c53d..e2ca351a4 100644
--- a/td/telegram/Client.cpp
+++ b/td/telegram/Client.cpp
@@ -127,6 +127,7 @@ class ClientManager::Impl final {
         response.object->get_id() == td_api::updateAuthorizationState::ID &&
         static_cast<const td_api::updateAuthorizationState *>(response.object.get())->authorization_state_->get_id() ==
             td_api::authorizationStateClosed::ID) {
+      auto guard = concurrent_scheduler_->get_main_guard();
       auto it = tds_.find(response.client_id);
       CHECK(it != tds_.end());
       it->second.reset();