error in installing causalTree

[colevfrank]

I am trying to install causalTree and am receiving the following message:

install_github("susanathey/causalTree")
Downloading GitHub repo susanathey/causalTree@master
Error in utils::download.file(url, path, method = method, quiet = quiet, :
cannot open url 'https://api.github.com/susanathey/causalTree/tarball/HEAD'

I'm on Windows Server 2016 and using R 4.1.2. Do I need do be using an earlier version of R for compatibility with the causalTree package?