Admin Login Stopped

Hello , i am running wordpress version 4.5
and bought theme newspaper

i was working very well in my admin page until
i cleared the cache in my browser history and now i cant
log in anymore , i changed the password with phpmyadmin
i passed through emergency.php too the last choice to recover
the password but its not that . they are fine

i dont know what is causing this problem but i really need help
and i have installed security plugins for protection i think
that maybe caused my problem but istill need an answer please ?