I am able to receive e-mail, but not send. I've tried looking through my cPanel to make sure passwords are correct and no one else has accessed my account.
The access logs don't appear to have a year date on them, but it looks like someone may have both posted files on my site and taken them down today. Is it possible someone has changed the password for my default e-mail without changing my password for my cpanel login? I thought they were always the same. If they aren't, how can I check on it and change it if needed?
Update: Upon further checking, it looks like someone tried to access outdated links to files posted to my site a couple of years ago. They're no longer available, so whoever was checking the old links got a file not found error. This is what I saw in the logs and misread. I still find it odd that this happened on the same day I am having trouble sending e-mail. Ideas?

Blech! I've been trying to figure out what's going on by reading this Thunderbird threads:
http://getsatisfaction.com/mozilla_messaging/topics/password_problem_login_failedhttp://getsatisfaction.com/mozilla_messaging/topics/can_not_send_mail_smtp_errorI've tried the suggestions about switching from STARTTLS to SSL/TLS and switching from Port 45 to Port 465. These gave me varying SMTP error messages, but still not making it work. This is my current error message with SSL/TLS and Port 465. I don't want to try no name/password, but I'm beginning to wonder if that's the only way I'll ever send e-mail again!

Sending of message failed.
The message could not be sent using SMTP server paperspast.com for
an unknown reason. Please verify that your SMTP server settings
are correct and try again, or contact your network administrator.