can't receive messages from the outside

[koax]

hi,

i`ve installed roundcube on my server a few days ago but instead of getting any better concerning my problems it`s getting worse.
in the moment i can't receive emails that come from outside my server (another webmailer f.e.). when i'm sending from another email-adress with the same domain name, it works. so inside the system they can send and receive messages, but if i'm trying to send something from my gmail account nothing appears in my inbox.

[koax]

i believe it`s not roundcube`s fault. but what should i do? what is the problems source?
i`ve got a dedicated server running on Linux (Suse with Plesk.)

[koax]

i've fixed it.

[SKaero]

Can you tell us how you fixed it so that if some one else have has this problem they can fix it.

[koax]

i've done my roundcube installation with the help of paul stamatiou's HOW TO.

ok. my installation directory for roundcube is http://mydomain.org/mail
i also wanted to install it @: http://mail.mydomain.org

by creating the subdomain i turned of my imap/mail server or something like that.
i just made a new DNS entry called mail.mydomain.org and entered my IP-adress to have it once again.
that was the clue.

p.s.:
my entries for mail host is:
$rcmail_config['default_host'] = 'mail.helve.org';
and my smtp host is:
$rcmail_config['smtp_user'] = '';
(all can be found at the main.inc.php file in the config directory of roundcube)