diff --git a/combo/public/views.py b/combo/public/views.py
index 4797ff8f..12031b57 100644
--- a/combo/public/views.py
+++ b/combo/public/views.py
@@ -146,7 +146,7 @@ def ajax_page_cell(request, page_pk, cell_reference):
 
         if action_response:
             response = HttpResponse(
-                action_response.content, content_type=action_response.headers['Content-Type']
+                action_response.content, content_type=action_response.headers.get('Content-Type')
             )
             if 'Content-Disposition' in action_response.headers:
                 response['Content-Disposition'] = action_response.headers['Content-Disposition']