I have a leased server that I use cpanel and webhost manager to manage. I've just set up the server in the past week and put our website on it and created all the email accounts. The emails are all working fine now, but we have another website on someone elses server that has sends an email (using php) and the emails aren't going through.

They went through just fine before I moved our site and email accounts over, and I've checked in cpanel to see if I had any spam filters turned on and I don't. I've also tried sending email manually using thunderbird and outlook, both work fine. Also, on our server, i've been able to send email through php.

Anyone know of a setting that I might be missing in my webhost manager?

thanks in advance.