i can't view any post

hello, ( i don’t why my previous post was deleted and closed so i’am re-posting it and sorry)

i’ve had a strange problem today that i don’t understand why it appeared as i didn’t install any new plug-in in the past days
but just 5 hours ago the problems appeared.

( the problem is whatever i type in the address ( that leads to a valid post or a categorize or read more or next page ) the only thing that appear is the first page but the URL changed

( i tried the twenty theme and same problem, cleared the cache and disables it too )

(url: http://www.smart4fun.com )