Login sistem mengguakan session

Web Google sore gan, mau nanya terkait login sistem menggunakan SESSION, sy kan pake hosting gratis di 000webhostapp.com, nah pas mau login di web yang sdh sy hosting malah muncul error padahal kalo di xampp normal aja, errornya seperti ini : Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /storage/ssd5/247/8865247/public_html/admin/login.php:1) in /storage/ssd5/247/8865247/public_html/admin/login.php on line 76

Warning: Cannot modify header information - headers already sent by (output started at /storage/ssd5/247/8865247/public_html/admin/login.php:1) in /storage/ssd5/247/8865247/public_html/admin/login.php on line 78

0){ session_start(); $_SESSION['nama']== $nama; header('location: index.php');

} else { $msg = "gagal Login user & password anda salah"; echo ""; } }

?>