Contact form 7 plugin – intranet blog – ms exchange 2003

I am new to wordpress and I am working on a intranet blog for our small company of about 120 employees. I have it set up and added the contact form 7 plugin so employees could send private emails, but when I send it’s not working. I get the red boarder message. We are hosting this internally on a in house server. Our mail which we host in house as well in ms exchange 2003. I used the default setup that comes with contact form 7 no customization was done. any help will be greatly appreciated.