[JoshKurtz]

I can't send email from Mail no matter which account I use. It gives me a screen asking if I'd like to try sending the message from another account but that doesn't work. My SMTP settings are the same as yesterday, when it worked. I can send mail from Safari or Firefox or other computers in my house so I think it's something within Mail. I have a gmail account for all my accounts.
I repaired permissions with no luck and I restarted with no luck.
Any ideas?

[L3Training]

If web based mail works then my guess is you're having problems with SMTP - which you mentioned.

Have you verified the SMTP service is still available from where you were trying to send mail? It could be a firewall problem. A quick port scan from Network Utility would answer the question of a firewall blocking the service. SMTP is on Port 25.

Did your network topology change recently - install any new network devices? Switch ISPs? Make changes in your network settings? Turn on the personal firewall in System Prefs?

[JoshKurtz]

My port scan came up clean but there's something going on with port 25 since I installed Entourage last night and had the same problem with it. I found it suggested on gmail's settings page that you use port 587 instead of 25 so I did that and voila, it works. Now I have to figure out why I can't recieve any mail. Sheesh! I feel like I'm playing Pop-a-Mole.

Okay, got that fixed too. Moles all gone.