这可能晚了，但对于未来的访问者来说，

Well this might be late but for future visitors,

我当时发现 biz.nf 拒绝从外部来源连接到它的数据库，这意味着只有 biz.nf 可以访问他们的数据库，但您会被拒绝.

I found out back then that biz.nf refuses any connections to it's DB from outside source which means that only the web-apps hosted on biz.nf have the access to their DB other than that you will get rejected.