git2r push error timeout. Proxy issue ?

[gse-cc-git]

Hello, I' am interested in using the package archivist.github which (from what I understand) rely internally on git2r for pushing object to a remote repository.

Using the archivist.github::archive function I get the following error:

Error in .local(object, ...) : 
  Error in 'git2r_push': failed to send request: timeout 

Has it something to do with a proxy configuration ? Also I am using a portable version of git. Thanks

git2r version: git2r 0.18.0 2017-01-01 CRAN (R 3.3.2)

Edit: it works from home on a linux, so seems to me that it has smthing to do with proxy setting, but I'm lost on how to do...