Error: 404 Not Found

Sorry, the requested URL 'http://u.limo/wp-admin/admin-ajax.php?channel_id=social_wechat&action=xh_social_channel&tab=login_redirect_to_authorization_uri&xh_social_channel=44368a18eb&notice_str=9149530923&hash=b7f3624770774cd05dde143a8d0e9a5f&redirect_to=https%3A%2F%2Fu.limo%2F14648%2F' caused an error:

Not found: '/wp-admin/admin-ajax.php'