diff --git a/src/calibre/gui2/tts/config.py b/src/calibre/gui2/tts/config.py
index 89a67bbdad..64bd00802e 100644
--- a/src/calibre/gui2/tts/config.py
+++ b/src/calibre/gui2/tts/config.py
@@ -572,7 +572,7 @@ class ConfigDialog(Dialog):
 
     def accept(self):
         engine_name = self.engine_choice.value
-        tts = create_tts_backend(engine_name)
+        tts = create_tts_backend(engine_name or None)
         s = self.engine_specific_config.as_settings()
         if not tts.validate_settings(s, self):
             return