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=7814ef69ff&notice_str=6656171822&hash=e7fa1d033218e2d70857a17e7721c82a&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E8%25BD%25AC%25E5%259C%25BA%25E6%25A8%25A1%25E6%259D%25BF%2F' caused an error:

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