empty startup greeting localhost:143

[ornejedediah]

HI there; i have roundcube 1.5 beta. Today i tryed to enable password plugin but after some try  i cannot login anymore with the mail server.
in logs i find
[09-Nov-2021 18:14:23 +0100]: <6qcoh834> IMAP Error: Login failed for USER@DOMAIN.it against localhost from 80.244.121.76. Empty startup greeting (localhost:143) in C:\xampp\htdocs\roundcube\program\lib\Roundcube\rcube_imap.php on line 210 (POST /?_task=login&_action=login)

i tryed to modify config file in this line
$config['default_host'] = 'localhost';
instead of localhost i tryed local ip address, ip public address, DOMAIN.IT adn so on but nothing changes i always have this error in log.
I saw many posts related to ssl/TLS that try to change the prev line in 'ssl//my.domain.it' but there is no way to fix this.
Can some one help me?
thanks