Need Configuration Settings

I have developed flex based application with php. My client is using Windows 2003 Server. I installed IIS Server and Php Installer into my client machine. I configured php into IIS Server and its working fine.

Query: I wrote a mail code for sending mail to my application user. My client is using internal mail server. I want to send a mail through my application. I used smtp.gmail.com into my application and Its 开发者_运维问答working perfectly. But when I am using client internal mail server. It is showing below mentioned error.

"Failed to set sender [SMTP: Invalid response code received from server. (Code: 554, response: Mail from mail-id rejected for policy reasons.]"

Please help me out to solve this query. Thanks in advance.

Well, why not to ask client's system administrator about "policy reasons"?

This should be no PHP problem but rather a problem with the SMTP server or a misconfiguration of the SMTP settings in your application. SMTP servers can be equipped with a lot of security features (I think that's what they mean with policy reasons) to allow or deny sending emails through that server from specific hosts, from specific uses, with specific authentication mechanisms, to specific domains, to specific users, etc. (list can be continued endlessly). Contact the responsible system administrator for that SMTP server and ask him what settings you need to feed into your SMTP mailer in your application.