diff --git a/bootstrap.py b/bootstrap.py
index 4eb9937..51313b7 100755
--- a/bootstrap.py
+++ b/bootstrap.py
@@ -37,17 +37,21 @@ with open('servers.json', 'r') as server_fh:
     MODULES = jsonfile['modules']
 
 
-async def set_linked_multi_variables(linked_server: str,
+async def set_linked_multi_variables(value: str,
+                                     linked_server: str=None,
                                      **kwargs: dict,
                                      ) -> None:
-
+    if value is not None and linked_server is not None and 'linked_value_0' not in kwargs:
+        kwargs['linked_value_0'] = value
+    elif linked_server is None:
+        linked_server = value
     if linked_server is None:
         return
     if linked_server not in CONFIGS:
         warn_explicit(ValueWarning(f'cannot find linked server "{linked_server}"'),
                       ValueWarning,
                       __file__,
-                      0,
+                      3,
                       )
         return
     config = CONFIGS[linked_server][0]
@@ -74,27 +78,35 @@ async def set_linked_multi_variables(linked_server: str,
     dynamic = None
     slave_idx = None
     await config.property.read_write()
+    first_variable = variables[0]['value']
+    if not isinstance(variables[0]['value'], list):
+        variables[0]['value'] = [variables[0]['value']]
     try:
-        for index in sorted(list(variables)):
-            path = variables[index]['path']
-            value = variables[index]['value']
-            if dynamic:
-                path = path.replace('{suffix}', dynamic)
-            else:
-                dynamic = normalize_family(value)
-            option = config.forcepermissive.option(path, slave_idx)
-            multi = await option.option.ismulti()
-            if multi and await option.option.isfollower():
-                multi = await option.option.issubmulti()
-            if multi:
-                values = await option.value.get()
-                if value not in values:
-                    values.append(value)
-                    await option.value.set(values)
-                if await option.option.isleader():
-                    slave_idx = values.index(value)
-            else:
-                await option.value.set(value)
+        for var_index in range(len(variables[0]['value'])):
+            pass
+            for index in sorted(list(variables)):
+                path = variables[index]['path']
+                if index == 0:
+                    value = variables[index]['value'][var_index]
+                    dynamic = normalize_family(value)
+                else:
+                    value = variables[index]['value']
+                    path = path.replace('{suffix}', dynamic)
+                option = config.forcepermissive.option(path, slave_idx)
+                multi = await option.option.ismulti()
+                if multi and await option.option.isfollower():
+                    multi = await option.option.issubmulti()
+                if multi:
+                    values = await option.value.get()
+                    if value not in values:
+                        values.append(value)
+                        await option.value.set(values)
+                    if await option.option.isleader():
+                        slave_idx = values.index(value)
+                else:
+                    if isinstance(value, list):
+                        value = value[var_index]
+                    await option.value.set(value)
     except Exception as err:
         await config.property.read_only()
         raise err from err
@@ -324,6 +336,8 @@ def build_module(module_name, datas, module_infos):
     def calc_depends(appname, added):
         if appname in added:
             return
+        if appname not in applications:
+            raise Exception(f'cannot find application dependency "{appname}" in application "{module_name}"')
         as_dir = applications[appname]
         cfg.modules.append(appname)
         dictionaries_dir = join(as_dir, 'dictionaries')
@@ -488,7 +502,7 @@ async def valid_mandatories(server_name, config):
 async def templates(server_name, config, cfg, srv, int_idx):
     values = await config.value.dict()
     engine = RougailSystemdTemplate(config, cfg)
-#    if server_name == 'revprox.in.silique.fr':
+#    if server_name == 'dovecot.in.silique.fr':
 #        print()
 #        print(f'=== Configuration: {server_name} ===')
 #        pprint(values)
diff --git a/src/risotto/x509.py b/src/risotto/x509.py
index f6d41f1..54731c1 100644
--- a/src/risotto/x509.py
+++ b/src/risotto/x509.py
@@ -154,6 +154,8 @@ def gen_cert_iter(cn,
     if not isfile(cert_ca_name):
         raise Exception(f'cannot find CA file "{cert_ca_name}"')
     if not isfile(cert_name):
+        if not isfile(key_ca_name):
+            raise Exception(f"cannot find CA private key (\"{authority_cn}\") to sign certificat for \"{cn}\", is it a Let's Encrypt certification?")
         if not isdir(dir_name):
             makedirs(dir_name)
         if isfile(sn_name):