If you can’t send out any email messages, first double-check that all your outgoing settings are correct. If they are not, just correct them and try again. For Comcast for example, your Domain field should be left blank (see previous section Configure email for details).

If you are sure that all your settings are correct, and you can only receive email (POP account) but cannot send anything out, then chances are you should change your outgoing (SMTP) port. On a PC, it's a lot simpler to do. On a PDA, you'll need to download an SMTP Manager (a free software) that will allow you to change your SMTP port. I am very happy with this free download of SMTP Manager v2.0: http://www.freewareppc.com/communication/smtpmanager.shtml

By default, your SMTP port is 25. Change it to 465 or 587 and try again. If you get a message "Certificate invalid continue anyway?" just tap "Yes." On my PDA I use port 465. Once you have it set up correctly, you can use the same outgoing settings for several email accounts, even if they are from different IP providers. Your messages will still go out with your email address.