Help with Permalink

ok guys, so here what’s going on. I just installed wordpress on my website. I’m trying to change the permalinks to a custom structure, this one > http://ravanelliphotography.com/%postname% I want to show the Page’s title on the navigation bar (ex: ravanelliphotography.com/contact)

For some reason it’s not working, when I click on the link to the contact page appears a error, but if I add index.php before the /contact it work fine. It seem like I NEED the index.php to be there, which bothers me very much ahah….

PLEASEEE HELP, I can’t fix it, I already deleted index.php from the wp-content folder…