Javax Mail rejected as relay attempt

[jza]

I have a server solution running on Tomcat that is using Javax.Mail to send mails.

The mail is configured to use localhost port 25 as smtp host. This has worked at some point in time but now i get the following error message:

[2002.12.15 10:44:10]ERROR: (ShopManager.sendMail) : Exception caught
during mail transmission to localhost : Sending failed;
nested exception is:
javax.mail.SendFailedException: Invalid Addresses;
nested exception is:
javax.mail.SendFailedException: 554 <jza@ebit.dk>: Recipient
address rejected: Relay access denied
;
nested exception is:
javax.mail.SendFailedException: 554 <jza@ebit.dk>: Recipient
address rejected: Relay access denied

Localhost is IIS, and SMTP is configured to accept connections from anyone, and to allow relay (for now). I have verified that this server working as expected by sending mails from telnet.

Still Javax.mail is unable to use the host (or any other SMTP host). Any ideas?