Atmail not sending

[aoimacollamain]

Hi,
I've set up a new server and transferred a number of clients to it. I have included atmail in the install. However, when trying to send from atmail I get the following error:
Could not send message to SMTP server. Check you have access to send messages via the server and that all To/CC/BCC addresses are valid\nError: SMTP Server rejected email. Returned:550 authentication required

What could be causing this?
Thanks
Steve Jacobs

[scsi]

Your /etc/exim.conf is wrong probably.

http://help.directadmin.com/item.php?id=51

Do other webmail programs do the same?

Try to update atmail.

cd /usr/local/directadmin/custombuild
./build update
./build clean
./build atmail d

[aoimacollamain]

Thank you scsi. I tried all instructions including running the exim.conf updates, checking exim.conf, and then updating atmail. I have squirrelmail installed and it works fine. Still have same error with atmail.
Steve

[ehsanch]

io added "127.0.0.1" to /etc/virtual/whitelist_hosts and it worked.

[pera]

io added "127.0.0.1" to /etc/virtual/whitelist_hosts and it worked.
Thanks this help me to had exact same message and problem.