This is funny because I had this problem on a local server on my network too. Anywho, I have a php script that uses the mail() to send mail(which its not doing). And if I recall the mail function uses the prompt command MAIL, which does not work. What can I do to get the MAIL command working (i forgot how to get it to work, or what to install I should say), and is that maybe why the php mail() is not working? According to the php ini file it is configured to be able to send mail. Exim, PHP/4.3.3. This problem may go deeper than I think, I just checked some logs in cpanel and it appears as though most domains (yahoo.com and msn.com) are coming back as unroutable for mail(yes they are valid email addresses).


List of errors
--------------

1 xxx@bob.net R=fail_remote_domains: unrouteable mail
domain "bob.net"

2 xxx@yahoo.com R=fail_remote_domains: unrouteable
mail domain "yahoo.com"

18 xxx@gmail.com R=fail_remote_domains: unrouteable
mail domain "gmail.com"

1 xxx@stevenetworks.com R=fail_remote_domains: unrouteable
mail domain "stevenetworks.com"

7 xxx@porteightyhosting.com.com
R=fail_remote_domains: unrouteable mail domain "porteightyhosting.com.com"

28 xxx@stevenetworks.com R=fail_remote_domains: unrouteable
mail domain "stevenetworks.com"

7 xxx@msn.com R=fail_remote_domains: unrouteable
mail domain "msn.com"

1 xxx@stevenetworks.com R=fail_remote_domains: unrouteable
mail domain "stevenetworks.com"

26 xxx@yahoo.com R=fail_remote_domains: unrouteable
mail domain "yahoo.com"

148 xxx@s1.porteightyhosting.com :
Unrouteable address

I know this error shows up if there is some kind of email throttling in place.. for example if you send out a message to 100 people, and the limit is set to 50 per message.. the last 50 recipients would show up in this error message saying 'unroutable domain', etc.

Are you trying to send a bulk/large email?
Does it have a large amount of CC or BCC recipients?

I know this is bumping an old topic, but I just had this error, and found out the cause.

If you have a cPanel server installed, go to tweak settings in WHM, and turn off 'Disable nobody from sending mail', so that the user nobody CAN send mail.

I got this problem from uninstalling phpsuexec, but not redoing that setting.