@kevinushey apparently there was some weird connectivity issue, because in the following days I was able to install_github without having to configure any proxy. Anyway, thanks for the link! Can I tweet about it? It could be useful for people using R in a company.
Anyway, I have to say that the R ecosystem is the most proxy/firewall-friendly I've ever worked with
- I've been able to install.packages() and update RStudio for years without having to configure a single proxy, much unlike Python's pip for example.