error about download cfdr

i attempt to download cfdr using following code:
> library("devtools");
> install_github("jamesliley/cfdr")
but error is present: 
Downloading GitHub repo jamesliley/cfdr@master
Error in utils::download.file(url, path, method = download_method(), quiet = quiet,  : 
  cannot open URL 'https://api.github.com/repos/jamesliley/cfdr/tarball/master'