[exim] Unable to send mails from Mail Clients

Hi all,

I configured Exim as SMTP server and Dovecot as IMAP server for my
organization. Using squirrelmail Iam able to send and receive mails from
any domains.

But from mail clients (outlook/thunderbird/evolution), I able to receive
mails from all the domains but unable to send mails to other domains
except my domain(seec-india.com).

What could be the reason? Iam unable to find the problem. Please help
me to fix the problem.

Thanks in Advance,
C V Kishore
Systems Administrator
SEEC Technologies Asia Pvt. Ltd.