diff --git a/radicale/acl/LDAP.py b/radicale/acl/LDAP.py
index 32d0319..d6934ee 100644
--- a/radicale/acl/LDAP.py
+++ b/radicale/acl/LDAP.py
@@ -39,10 +39,18 @@ SCOPE = getattr(ldap, "SCOPE_%s" % config.get("acl", "ldap_scope").upper())
 
 def has_right(owner, user, password):
     """Check if ``user``/``password`` couple is valid."""
+    global CONNEXION
+
     if not user or (owner not in acl.PRIVATE_USERS and user != owner):
         # No user given, or owner is not private and is not user, forbidden
         return False
 
+    try:
+        CONNEXION.whoami_s()
+    except:
+        log.LOGGER.debug("Reconnecting the LDAP server")
+        CONNEXION = ldap.initialize(config.get("acl", "ldap_url"))
+
     if BINDDN and PASSWORD:
         log.LOGGER.debug("Initial LDAP bind as %s" % BINDDN)
         CONNEXION.simple_bind_s(BINDDN, PASSWORD)