diff --git a/src/risotto/machine.py b/src/risotto/machine.py
index 84fa5e7..4e915f9 100644
--- a/src/risotto/machine.py
+++ b/src/risotto/machine.py
@@ -334,7 +334,7 @@ class Loader:
     def add_tls(self):
         dns_module_name = None
         for host in self.servers_json['hosts'].values():
-            zones = [self.servers_json['zones']['external_zone']]
+            zones = [self.servers_json['zones']['external_zone'], None]
             for server_name, datas in host['servers'].items():
                 if not 'applicationservice' in datas:
                     raise Exception(f'cannot find applicationservice for "{server_name}"')
@@ -345,8 +345,8 @@ class Loader:
                     if dns_module_name:
                         break
                     zones[1] = datas['provider_zone']
-            if zones[0] == zones[1]:
-                zones = [zones[0]]
+            if zones[0] == zones[1] or not zones[1]:
+                zones.pop(1)
             host['servers']['tls'] = {'applicationservice': 'tls',
                                       'zones_name': zones,
                                       }