The warning message you're receiving indicates that your SMTP server is configured as mail.uah.es, and you're connecting on port 25, which is the standard SMTP port. The warning indicates that the server couldn't be reached at that configuration, which means you're using the wrong server, or there is a network problem between your machine and the server, or that your server requires connections on a different port (i.e. if it requres messages to be delivered over SSL). Are you able to deliver mail to that server using an email program i.e. Thunderbird? If your ISP has instructions for configuring a mail program, it might be helpful to look through those.
Public Knowledge Project Team