The most common reason that abdicar.com's customers are unable to send emails through Outlook Express are that they have the wrong Outlook Express settings, a blocked PORT 25 by their ISP (Internet Service provider), or lean SMTP authorization is required.
We discussed the solution to a blocked PORT 25 in another knowledgebase article. Simply follow the link to the Blocked PORT 25 article that is already part of the Knowledge Base, and you will find the solutions you are looking for.