Emails aren't sent or received - emails moved to outbox - open emails to see what's wrong

Since 2:07 am today, my Comcast emails aren't being sent or received on my android Galaxy S series. I tried to send a test message to my own email address. It gets moved to my outbox with the message: "Couldn't send." I select the email that didn't send and it says: "Couldn't authenticate...the password or authentication method may be incorrect. Check your outgoing server settings, then try again." I then selected: "Settings" and it brings up the "Server settings" screen. I don't know what the fields should be, but haven't changed anything to my phone or settings or done a phone update. I did a soft and hard restart (pushed the down volume and power button together until restarted), but still not working. I can send and receive emails if I go directly to Comcast's email site. Help.