diff --git a/moler/command_scheduler.py b/moler/command_scheduler.py
index 37c5823de..d0b44a224 100644
--- a/moler/command_scheduler.py
+++ b/moler/command_scheduler.py
@@ -3,7 +3,7 @@
 """Scheduler for commands and events."""
 
 __author__ = "Marcin Usielski"
-__copyright__ = "Copyright (C) 2019-2023, Nokia"
+__copyright__ = "Copyright (C) 2019-2025, Nokia"
 __email__ = "marcin.usielski@nokia.com"
 
 import logging
@@ -43,6 +43,8 @@ def enqueue_starting_on_connection(connection_observer):
         )
         t1.daemon = True
         t1.start()
+        connection_observer._log(logging.WARNING, f"Requested to execute command ({connection_observer}) but the other "
+                                 "command is running. Waiting for a free slot.")
 
     @staticmethod
     def dequeue_running_on_connection(connection_observer):
diff --git a/moler/connection_observer.py b/moler/connection_observer.py
index c6cc670d9..c8dc13777 100644
--- a/moler/connection_observer.py
+++ b/moler/connection_observer.py
@@ -3,7 +3,7 @@
 """Base class for all events and commands that are to be observed on connection."""
 
 __author__ = "Grzegorz Latuszek, Marcin Usielski, Michal Ernst"
-__copyright__ = "Copyright (C) 2018-2024 Nokia"
+__copyright__ = "Copyright (C) 2018-2025 Nokia"
 __email__ = (
     "grzegorz.latuszek@nokia.com, marcin.usielski@nokia.com, michal.ernst@nokia.com"
 )
@@ -546,7 +546,7 @@ def get_short_desc(self) -> str:
         """
         return f"Observer '{self.__class__.__module__}.{self}'"
 
-    def _log(self, lvl: int, msg: str, extra: dict = None, levels_to_go_up: int = 1) -> None:
+    def _log(self, lvl: int, msg: str, extra: Optional[dict] = None, levels_to_go_up: int = 1) -> None:
         """
         Log a message with the specified level.