diff --git a/app/overrides/subnets/_fields/opennebula_fields.html.erb.deface b/app/overrides/subnets/_fields/opennebula_fields.html.erb.deface
index 3aea624..9958842 100644
--- a/app/overrides/subnets/_fields/opennebula_fields.html.erb.deface
+++ b/app/overrides/subnets/_fields/opennebula_fields.html.erb.deface
@@ -1,4 +1,4 @@
 <!-- insert_after ':root:last-child' -->
 
-<%= select_f f, :opennebula_vnet, ForemanOpennebula::Opennebula.first.available_networks, :id, :name, { include_blank: true },
+<%= select_f f, :opennebula_vnet, ForemanOpennebula::Opennebula.first&.available_networks, :id, :name, { include_blank: true },
 :label => _("OpenNebula Virtual Network"), :help_inline => _("Reference at OpenNebula Virtual Network object") %>