Excellent it is working fine now..
Thanks alot for your unmatchable support.

The configuration i have used is below:
Mailer- SMTP Server
SMTP Security - ssl
SMTP PORT - 465
Mail from - webmaster@mydomain.com
send mail path - /usr/sbin/sendmail
SMTP Authentication- yes
SMTP USER NAME- webmaster@mydomain.com
password-*******
SMTP Host- mail.mydomain.com

But the error at the end of test given is
"SMTP Error! The following recipients failed:"

Other mail are sent correctly
i have no problem in mail settings

I am sending the screen shot of the setting where i have problem. in quiz there is colomn by name additional setrtings, under that there is an option "send results to" under that e-mail, if i fill the column by my email id and save, and when i take test at the end error message will appear. if i leave that blank no error is found, but i need the test results to be sent to my email, Please do help in this.

in quiz there is colomn by name additional setrtings, under that there is an option "send results to" under that e-mail, if i fill the column by my email id and save, and when i take test at the end error message will appear. if i leave that blank no error is found, but i need the test results to be sent to my email, Please do help in this.

in quiz there is colomn by name additional setrtings, under that there is an option "send results to" under that e-mail, if i fill the column by my email id and save, and when i take test at the end error message will appear. "SMTP Error! The following recipients failed:"
if i leave that blank no error is found, but i need the test results to be sent to my email, Please do help in this.

We can try to help you, if you provide temporary access to your Joomla! backend by email that we can investigate this issue.

Regards,
ARI Soft