HeavyFrost on "[Plugin: Contact Form 7] Failed to send your message."

I've received this error after I installed the plugin and put it on my contact page. (I am using a gmail account)
Failed to send your message. Please try later or contact the administrator by another method.
If you need more information or know a way to resolve this issue feel free to comment.

http://wordpress.org/plugins/contact-form-7/