Me enfrento a este problema cuando intento descargar e instalar un paquete desde git-hub usando devtools.

Versión R: 3.1.3 (64 bit)

> install_github("hadley/httr")
Downloading github repo hadley/httr@master
Error in curl::curl_fetch_memory(url, handle = handle) : 
  Timeout was reached

> traceback()
13: .Call(R_curl_fetch_memory, url, handle)
12: curl::curl_fetch_memory(url, handle = handle)
11: request_fetch.write_memory(req$output, req$url, handle)
10: request_fetch(req$output, req$url, handle)
9: request_perform(req, hu$handle$handle)
8: httr::HEAD(src_submodules, , auth)
7: github_has_remotes(x, auth)
6: remote_download.github_remote(remote, quiet = quiet)
5: remote_download(remote, quiet = quiet)
4: FUN(X[[1L]], ...)
3: vapply(remotes, install_remote, ..., FUN.VALUE = logical(1))
2: install_remotes(remotes, ...)
1: install_github("hadley/httr")

Ediciones:

Estoy usando Revolution R Enterprise 7.4 con un cliente Rstudio.