[imp] Mail not getting sent from server queue

[Arjun Xavier]

I have this id arjun at brahmaait.com from webmail.brahmaait.com. It is a horde account. The problem is, I am not able to send mails to rediffmail accounts. We use account from webmail.brahmaait.com to send news letters to our clients. We can send mails to all other e-mail providers except rediffmail.com, whenever we send emails to rediffmail accounts, the messages are getting queued in the server, it is not going from the server, so it is not getting delivered to rediff mailbox. I am not getting any error messages.
This is a very serious matter and please provide a solution for this problem as fast as possible. 

Thanks and regards,

Arjun Xavier

Brahmaa Infotek,
XI/369 B, I Floor, Gloria,
Mavelipuram, Kakkanad,
Kochi, Kerala - 682030
Phone: +91-4846455222
Mobile: +91-9961262820