diff --git a/radicale-auth-ldap/__init__.py b/radicale-auth-ldap/__init__.py
index 65989cc..fb66c85 100644
--- a/radicale-auth-ldap/__init__.py
+++ b/radicale-auth-ldap/__init__.py
@@ -125,6 +125,11 @@ class Auth(BaseAuth):
         accessGroupFilter = self.configuration.get("auth", "ldap_access_group_filter")
         accessGroupAttribute = self.configuration.get("auth", "ldap_access_group_attribute")
 
+        if password == "":
+            logger.error("LDAP: user password is mandatory")
+
+            return ""
+
         if self.grantedUserAccessCache is not None:
             logger.info("LDAP: check if user is cached")