**Symfony version(s) affected**: 4.4+ **Description** Commit identified : https://github.com/symfony/ldap/commit/ebc066be4a3e56c93c7978a0765f2f00722d9e51#diff-417a42cf16696cf4f1941a331a2007f9 Manual page : https://www.php.net/manual/en/function.ldap-errno.php Apparently, only the ```ConnectionException``` is thrown. **Possible Solution** Use the hexadecimal notation : ```php private const LDAP_INVALID_CREDENTIALS = 0x31; private const LDAP_TIMEOUT = 0x55; private const LDAP_ALREADY_EXISTS = 0x44; ```