diff --git a/djangocms_forms/cms_plugins.py b/djangocms_forms/cms_plugins.py
index 3d57c74..af21136 100644
--- a/djangocms_forms/cms_plugins.py
+++ b/djangocms_forms/cms_plugins.py
@@ -107,7 +107,7 @@ class FormPlugin(CMSPluginBase):
         try:
             form_slug = "form-%d" % instance.plugin_reference.id
         except:
-            pass
+            form_slug = ""
         submission_instance = instance
 
         if request.session.get(form_slug, False):