Wordpress-警告:无法修改标题信息-函数.php中的wp_enque_style(谷歌字体）错误

我在我的域上转移了wordpress，当我尝试登录时，我收到了这个错误：

ERROR: Cookies are blocked due to unexpected output.

带有以下警告：

Warning: Cannot modify header information - headers already sent by (output started at /customers/e/2/2/myurlsite.com/httpd.www/wp-content/themes/twentythirteen-child/functions.php:10) in /customers/e/2/2/myurlsite.com/httpd.www/wp-login.php on line 424 
Warning: Cannot modify header information - headers already sent by (output started at /customers/e/2/2/myurlsite.com/httpd.www/wp-content/themes/twentythirteen-child/functions.php:10) in /customers/e/2/2/myurlsite.com/httpd.www/wp-login.php on line 437

我知道这个问题在我的functions.php文件中，但我不知道如何解决它，因为我对php一无所知。这是第10行的函数.php代码

<?php
add_action( 'wp_enqueue_scripts', 'wpsites_google_fonts' );
function wpsites_google_fonts() {
wp_enqueue_style( 'gfonts', '//fonts.googleapis.com/css?family=Oswald|Open+Sans|Euphoria+Script|Cookie', array(), CHILD_THEME_VERSION );
}
?>

有人能告诉我这个文件的问题在哪里吗？感谢