Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, function "wp_initialize_theme_preview_hooks" not found or invalid function name in /wp-includes/class-wp-hook.php:307
Stack trace:
#0 /wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters(NULL, Array)
#1 /wp-includes/plugin.php(474): WP_Hook->do_action(Array)
#2 /wp-settings.php(450): do_action('plugins_loaded')
#3 /wp-config.php(92): require_once('/wp-settings.ph...')
#4 /wp-load.php(50): require_once('/wp-config.php')
#5 /wp-blog-header.php(13): require_once('/wp-load.php')
#6 /index.php(17): require('/wp-blog-header...')
#7 {main}
thrown in /wp-includes/class-wp-hook.php on line 307