[acuartero]

Skn,

I assume that when you say the recipient's email address is the same you mean that they are both in the same domain. The 550 error is telling you that you cannot send (relay) email from OTM through your smtp server to another domain. However sending email to a user on the same domain is not affected. This is usually the default out of the box configuration for most email servers to prevent SPAM from being forwarded through open relays. What you need to do is to configure your smtp server to accept relays from either the internal subnet that the OTM app server is on or the specific IP for the app server if you don't want to allow relaying to everyone on the subnet. If you're using sendmail I would check out sendmail.org for more info on specific configurations.

Thanks,
Alan