The issue can be one of two reasons:
1. Make sure your email client is set the your Outgoing Server Requires Authentication
2. More and more ISP's (Internet Service Providors) are filtering outbound port 25 (SMTP) connections to many hosts, including ours, in order to force you to use their services. We offer port 26 SMTP in order to try and work around this problem. You can often set your email client to use port 26 for outbound email in order to use the You Got Net SMTP service that comes with your account.