iTunes says "Does not recognize content for Michelles iPhone," I cannot sync anything with my mac

I am trying to take my iPhone 5 and sync with my Mac, since day one it says "cannot recognize this device" this is in iTunes and Wants to to restore. I tried the "delete one song thing" and that didn't work. Tried the i-fun but when I download it I am unable to search anything...HELP!!! Step by step please