diff --git a/nanobot/channels/telegram/runtime.py b/nanobot/channels/telegram/runtime.py
index 9e42b2df..4ac83ca7 100644
--- a/nanobot/channels/telegram/runtime.py
+++ b/nanobot/channels/telegram/runtime.py
@@ -729,7 +729,7 @@ class TelegramChannel(BaseChannel):
         """Send a message through Telegram."""
         if not self._app:
             self.logger.warning("bot not running")
-            return
+            raise RuntimeError("Telegram bot is not running")
 
         progress_event = msg.event if isinstance(msg.event, ProgressEvent) else None