Login Issues

On WordPress 4.3.1, when logging in from wp-login.php, I can access the login page but see errors. However, after logging in with my credentials, both wp-admin.php and wp-login.php will load to a white page with just errors:
wp-login.php shows:
Warning: Cannot modify header information – headers already sent by (output started at /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-includes/user.php:9) in /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-login.php on line 431

Warning: Cannot modify header information – headers already sent by (output started at /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-includes/user.php:9) in /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-login.php on line 444

Warning: Cannot modify header information – headers already sent by (output started at /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-includes/user.php:9) in /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-includes/pluggable.php on line 935

Warning: Cannot modify header information – headers already sent by (output started at /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-includes/user.php:9) in /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-includes/pluggable.php on line 936

Warning: Cannot modify header information – headers already sent by (output started at /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-includes/user.php:9) in /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-includes/pluggable.php on line 937

Warning: Cannot modify header information – headers already sent by (output started at /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-includes/user.php:9) in /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-includes/pluggable.php on line 1207

wp-admin only shows:
Warning: Cannot modify header information – headers already sent by (output started at /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-includes/user.php:9) in /nfs/c04/h06/mnt/180548/domains/example.com/html/wp-includes/pluggable.php on line 1207

I assume I should be looking at user.php line 9… which is just a commented out statement:

<?php
/**
 * WordPress User API
 *
 * @package WordPress
 */
/**
 * Authenticate user with remember capability.
 *               (<--- This is line nine)
 * The credentials is an array that has 'user_login', 'user_password', and
 * 'remember' indices. If the credentials is not given, then the log in form
 * will be assumed and used if set.
 *
 * The various authentication cookies will be set by this function and will be
 * set for a longer period depending on if the 'remember' credential is set to
 * true.
 *
 * @since 2.5.0
 *
 * @param array $credentials Optional. User info in order to sign on.
 * @param bool $secure_cookie Optional. Whether to use secure cookie.
 * @return object Either WP_Error on failure, or WP_User on success.
 */