Hey all! I recently started having problems sending mail from my KH VPS. Here's my problem and what I've tried so far: PROBLEM: The following errors are received when sending from SMTP or a PHP mail function from my_domain.ORG TO my_domain.ORG. This also happens from webmail on my_domain.NET "lowest numbered MX record points to local host" "temporarily rejected RCPT: Could not complete sender verify." Here's my setup: mydomain.NET is an account on my VPS. It's using internal DNS and the http traffic works fine. I can send email to most domains just fine. mydomain.ORG is an account on my VPS. It's using external DNS set up by IT at my organization. All A record traffic is sent to my VPS IP address. The MX record points to our in-house Microsoft Exchange Server. Again, this problem happens when I'm sending mail from my_domain.ORG to my_domain.ORG (some of my PHP applications use php mail and some use SMTP using the my_domain.NET domain). Here's what I've tried: 1) I noticed my IT department didn't have host.my_domain.ORG DNS set up. It now resolves to my VPS IP address. 2) I tried: #Login to the WebHost Manager. #On the Service Configuration section,click on Exim Configuration Editor link. #Uncheck and untick the checkbox next to Use callouts to verify the existence of email senders. option. #Press the Save button, and cPanel will auto restart Exim. Did not work. 3) I tried # Go to /etc/localdomains and place my_domain.ORG entry there. There is no need to restart the ‘exim’ Tried this, but it didn't work. I restored it back to what it was before.