A temporary fix for me is to comment out the following line in the WP Spam Fighter plugin file named “wp-spam-fighter.php”
This is in no way a permanent solution. If anyone knows how to correctly fix this, please let me know.
Thanks!
public function register_hook_callbacks()
{
add_action('wpmu_new_blog', __CLASS__ . '::activate_new_site');
add_action('wp_enqueue_scripts', __CLASS__ . '::load_resources');
add_action('admin_enqueue_scripts', __CLASS__ . '::load_resources');
add_action('login_enqueue_scripts', __CLASS__ . '::load_resources');
add_action('comment_form_before', array($this, 'comment_form_before'));
add_action('comment_form_after_fields', array($this, 'comment_form_after_fields'), 1);
add_action('comment_form_logged_in_after', array($this, 'comment_form_after_fields'), 1);
add_action('pre_comment_on_post', array($this, 'pre_comment_on_post'));
add_filter('pre_comment_approved', array($this, 'pre_comment_approved'), 10, 2);
add_action('comment_post', array($this, 'comment_post'), 10, 2);
add_filter('preprocess_comment', array($this, 'verify_comment_captcha'));
add_action('register_form', array($this, 'register_form'));
add_action('signup_extra_fields', array($this, 'register_form'));
add_filter('registration_errors', array($this, 'registration_errors'), 10, 3);
add_filter('wpmu_validate_user_signup', array($this, 'wpmu_validate_user_signup'), 10, 1);
//add_action('init', 'session_start'); // Error: Warning: session_start() expects parameter 1 to be array, string given in C:\xampp\htdocs\imagedepotsandbox\wp-includes\class-wp-hook.php on line 286
add_action('init', array($this, 'init'));
add_action('init', array($this, 'upgrade'), 11);
}