调用auth.code2Session，后端控制报错host parameter is null？

拼接地址直接浏览器直接访问，返回报错

{"errcode":40125,"errmsg":"invalid appsecret, view more at http:\/\/t.cn\/RAEkdVq, hints: [ req_id: XfofIfyFe-8hbgWA ]"}