diff --git a/installer.cfg b/installer.cfg
index 5f4747a..cc2c066 100644
--- a/installer.cfg
+++ b/installer.cfg
@@ -25,7 +25,7 @@ dbname = modoboa
 dbuser = modoboa
 dbpassword = password
 # Extensions to install (you can use the 'all' shortcut)
-extensions = modoboa-admin modoboa-admin-relaydomains modoboa-admin-limits modoboa-amavis modoboa-pdfcrendentials modoboa-postfix-autoreply modoboa-sievefilters modoboa-stats modoboa-webmail
+extensions = modoboa-admin modoboa-admin-relaydomains modoboa-admin-limits modoboa-amavis modoboa-pdfcredentials modoboa-postfix-autoreply modoboa-sievefilters modoboa-stats modoboa-webmail
 
 [amavis]
 enabled = true
diff --git a/modoboa_installer/database.py b/modoboa_installer/database.py
index ac25148..67c354e 100644
--- a/modoboa_installer/database.py
+++ b/modoboa_installer/database.py
@@ -40,10 +40,13 @@ class PostgreSQL(Database):
         super(PostgreSQL, self).__init__(config)
         self._pgpass_done = False
 
-    def _exec_query(self, query):
+    def _exec_query(self, query, dbname=None, dbuser=None):
         """Exec a postgresql query."""
+        cmd = "psql"
+        if dbname and dbuser:
+            cmd += " -d {} -U {} -w".format(dbname, dbuser)
         utils.exec_cmd(
-            """psql -c "{}" """.format(query), sudo_user=self.dbuser)
+            """{} -c "{}" """.format(cmd, query), sudo_user=self.dbuser)
 
     def create_user(self, name, password):
         """Create a user."""
@@ -114,7 +117,7 @@ class MySQL(Database):
         utils.exec_cmd("echo '{}' | debconf-set-selections".format(cfg))
         super(MySQL, self).install_package()
 
-    def _exec_query(self, query):
+    def _exec_query(self, query, dbname=None, dbuser=None):
         """Exec a postgresql query."""
         utils.exec_cmd(
             """mysql -u {} -p{} -e "{}" """
diff --git a/modoboa_installer/scripts/modoboa.py b/modoboa_installer/scripts/modoboa.py
index ec53b02..ab78c38 100644
--- a/modoboa_installer/scripts/modoboa.py
+++ b/modoboa_installer/scripts/modoboa.py
@@ -103,7 +103,7 @@ class Modoboa(base.Installer):
                 "UPDATE lib_parameter SET value='{}' WHERE name='{}'"
                 .format(value, name)
             )
-            self.backend._exec_query(query)
+            self.backend._exec_query(query, self.dbname, self.dbuser)
 
     def post_run(self):
         """Additional tasks."""