I followed this link:
https://drupal.org/node/1107562

1. Go to Administration > People, permissions tab
2. Scroll down to the Contact sub title
3. Check the relevant roles and save
4. Now, go to Administration > Structure > Menus and click Navigation's list links
5. Enable Contact page by checking the box in the ENABLED column and save
6. If you like the contact form to be reached from the main menu, click the edit link next to Contact, and set parent link to <Main menu>