Boa tarde Senhores,   Estou tendo um problema, após alterar a versão do php de minha revenda   Warning: session_start(): Cannot send session cookie - headers already sent by (output started at /home/tapiocar/public_html/logar.php:1) in /home/tapiocar/public_html/logar.php on line 1

Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /home/tapiocar/public_html/logar.php:1) in /home/tapiocar/public_html/logar.php on line 1 <?php session_start(); ob_start();?> <!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <title>Logar</title> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta name="description" content=""> <meta name="author" content=""> <!-- Le styles --> <link rel="stylesheet" href="css/bootstrap.min.css" type="text/css"> <style type="text/css"> body { alguem poderia me dar uma luz       Obrigado