Mailsms help send mail or sms not work

Hi, I can not configure playsms with the mailsms plugin. I have a working mail server and I use postfix and dovecot, I have enabled the log level 3, but when I send the message to the system I do not receive any answer either on the email or on the phone. can you help me?

this is my error in the log

sendmail # end with error:535 5.7.8 Error: authentication failed:

but my credentials login is correct

this is the param on config.php:

$core_config[‘smtp’][‘relm’] = ‘’; // yes, not realm, it’s relm
$core_config[‘smtp’][‘user’] = ‘sms@…’;
$core_config[‘smtp’][‘pass’] = ‘password’;
$core_config[‘smtp’][‘host’] = ‘myhost’;
$core_config[‘smtp’][‘port’] = ‘25’;

can you help me?