Indiatimes.com — non delivery of sent emails

Address:

Mumbai Suburban, Maharashtra

My email id is: [protected]@indiatimes.com
Since last 2 days i am unable to send any emails from my a/c.
As soon as any email is sent, a message which reads as," undelivered mail returned to sender comes". & there is a failure in delivery.
Further, this is the message,
This is the mail system at host irmta6.indiatimes.com.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

host 192.168.24.78[192.168.24.78] said: 554 mail
server permanently rejected message (#5.3.0) (in reply to end of DATA
command)

Kindly guide ASAP