Email not working with Gmail?

Hello,
Im using A simple method to require visitors to submit an email before downloading a free file on my site.
The strange thing is that when i request the brochure, i get the message saying … “Brochure has been sent, please check your email!”

But when i check my gmail account ( the email i use to receive the brochre) i dont receive anything.

Now if i use another email provider (like hotmail or custom email ) I do get it?
Why does not work with Gmail?
Anyone have experience something similar??

thanks :/