I have Mac Mail checking and downloading email, but I can't get it to find the outgoing mail server. I've tried mail.blendergalactica.com, mail.www.blendergalactica.com, smtp.blendergalactica.com etc, but I get this error back:

The SMTP server “mail.blendergalactica.com” is not responding. Check your network connection and that you entered the correct information in the “Outgoing Mail Server” field. If it still doesn’t respond, the server might be temporarily unavailable.

If you continue, you may not be able to send any mail.

dear blendergalactica some isp block outgoing mail port
1- change mail software config
2 - change your isp
3 - you can use webmail ( http://www.yoursite.com/webmail )
i think you are dont make good config for your mail software
use this string for smtp and pop : mail.yoursite.com

After you create the account, go back in to prefrences and change the port from 587 to 25 and it works...I guess 587 must be a Mac Mail account.