Could not resolve host:

I didnot use proxy, when deploying an app, it comes out an error:

Preparing to deploy application...DONE
Uploading bundle for application: 1058619...Error in function (type, msg, asError = TRUE) :
Could not resolve host:
Calls: ... tryCatch -> tryCatchList -> tryCatchOne ->
Timing stopped at: 0 0.02 12.53
Execution halted

I also try to ping the url, report the same error:

Ping 请求找不到主机。请检查该名称,然后重试。

could anyone tell me how to resolve it? thx!