diff --git a/cterasdk/clients/clients.py b/cterasdk/clients/clients.py
index 3df1e8ce..de31961f 100644
--- a/cterasdk/clients/clients.py
+++ b/cterasdk/clients/clients.py
@@ -237,7 +237,7 @@ def multipart(self, path, form, *, on_response=None, on_error=None, **kwargs):
 
     @decorators.authenticated
     def delete(self, path, data=None, *, data_serializer=None, on_response=None, on_error=None, **kwargs):
-        request = async_requests.DeleteRequest(self._builder(path), data=data_serializer(data), **kwargs)
+        request = async_requests.DeleteRequest(self._builder(path), data=data_serializer(data) if data_serializer else None, **kwargs)
         return self.request(request, on_response=on_response, on_error=on_error)
 
     def _request(self, request, *, on_response=None, on_error=None):
@@ -407,10 +407,8 @@ def login(self):
 
 
 def execute(target, *args, **kwargs):
-    loop = asyncio.get_event_loop()
-
-    if not loop.is_running():
-        return loop.run_until_complete(target(*args, **kwargs))
+    if not event_loop.is_running():
+        return event_loop.run_until_complete(target(*args, **kwargs))
 
     return run_threadsafe(event_loop, target, *args, **kwargs)
 
diff --git a/cterasdk/convert/serializers.py b/cterasdk/convert/serializers.py
index f15887d9..6d6f041d 100644
--- a/cterasdk/convert/serializers.py
+++ b/cterasdk/convert/serializers.py
@@ -39,7 +39,9 @@ def _to_protected_dict(o):
 class Encoder(json.JSONEncoder):
 
     def default(self, o):
-        d = o.get('__dict__', None)
+        if isinstance(o, Exception):
+            return str(o)
+        d = getattr(o, '__dict__', None)
         if d:
             if '_classname' in d:
                 d['$class'] = d.pop('_classname')