What does a processx error mean when installing r packages with github_install?

Question

Using R 3.5.2 and devtools 2.0.1. When I use github_install("package_name") I keep getting the error:

Error in process_initialize(self, private, command, args, stdin, stdout, : processx error, create process: #1260 This program is blocked by group policy. For more information, contact your system administrator.

I am not an administrator, and my IT department limits what we install on our computers. However, I have no problem installing CRAN packages via install.packages().

So my questions are:

1. What does the error message mean?
2. Is there some difference between github_install and install.packages() I should be aware of that is causing this error?
3. Can anyone propose a fix / workaround so I can install packages from github.

An example package I tried to install below:

install.packages("devtools")
library("devtools")
devtools::install_github("ropenhealth/openfda")

This causes the error:

Error in process_initialize(self, private, command, args, stdin, stdout, : processx error, create process: #1260 This program is blocked by group policy. For more information, contact your system administrator.