Email form works on internet site – not on intranet site

Hi,

I’ve got a php form that sends me an email and works fine on my internet site but won’t send the email on the intranet site. I’m running iis and have a separate exchange server but not very well-versed on how the mail gets handled. Any ideas to step me thru getting it to send the email on my intranet site?

Thanks in Advance!!