If you get an error in the log file that looks something like "javax.mail.SendFailedException: 550 Unable to relay for my-address", then this means that you have a problem sending emails from VisionFlow.
All outgoing emails are sent from a common email server which is configured in the WEB-INF/classes/visionplatform_mail.properties file on your server
This is an error reply from your SMTP mail server and not a problem with VisionFlow itself. It indicates that your your email server is configured to not not allow users to send mail to external domain.
Typically, mail servers for an organization will be configured to allow mail from within the organization to be sent to other addresses within the organization, or to addresses external to the organization. It will also typically allow mail coming from an address external to an organization to be sent to addresses within the organization. What it will typically not allow is mail coming from an address external to the organization to be sent (relayed) to another address also external to the organization.
The configuration of the mail server determines whether such relaying is allowed, and which addresses are considered internal vs. external. Often mail servers will require you to authenticate before they will relay messages.
You need to allow relaying for the email accounts used by VisionFlow, such as the ones used by the ticket system(s) and the general email account configured
If you are using Microsoft Exchange, see here: http://blogs.technet.com/b/exchange/archive/2006/12/28/3397620.aspx