I can enter my homepage but can't enter wp-admin

Question

I build a wordpress site, for a time there was no problem but recently i can't enter my wp-admin page. I tried plugin,themes thing. I get this error but i dont know that it means. Can u help ?

Fatal error: Uncaught Error: Call to undefined method WP_Error::has_errors() in /var/www/html/wp-login.php:50 Stack trace: #0 /var/www/html/wp-login.php(937): login_header('Log In', '', Object(WP_Error)) #1 {main} thrown in /var/www/html/wp-login.php on line 50

Answer 1

Update your wp-login file with default Wordpress wp-login file.