SMTP Error (-1) Failed to set sender (USER NOT AUTHENTICATED)

[Nekac1]

Hello,
I have web hosting on certain domain (mydomain.com) and I set MX DNS record to adress to zoho mail (www.zoho.com). I installed roundcubemail on my domain (mail.mydomain.com) and set IMAPS and SMTS servers properly. I am able to connect to server and recieve emails, but when I try to send email, this message shows: SMTP Error (-1): Failed to set sender "user@mydomain.com" (USER NOT AUTHENTICATED).
mail/logs/errors says [20-Jun-2014 00:29:52 +0200]: SMTP Error: SMTP error: Failed to set sender 'user@mydomain.com' in /home/users/user_name/domain.com/sub/mail/program/lib/Roundcube/rcube.php on line 1504 (POST /?_task=mail&_unlock=loading1403216994402&_lang=en_US?_task=mail&_action=send)

Thanks for any suggestions regarding this issue.

[JohnDoh]

the error "USER NOT AUTHENTICATED" would suggest you need to configure smtp authentication in your Roundcube config file... see $config['smtp_user'] and $config['smtp_pass']

[Nekac1]

Thanks, I edited only /config/config.inc.php and I didn't know I should edit also /config/defaults.inc.php
Thanks again