fix

rowers/tasks.py

@@ -2069,7 +2069,10 @@ def handle_sendemail_breakthrough(workoutid, useremail,
                                   **kwargs):
 
     btvalues = pd.read_json(btvalues)
-    btvalues.sort_values('delta', axis=0, inplace=True)
+    try:
+        btvalues.sort_values('delta', axis=0, inplace=True)
+    except KeyError:
+        return 0
 
     lastname = ''