devtools::install_github() error

[andreamizzi]

I'm trying to install a package using devtools as I've done many times before, but now I get the following error:

devtools::install_github("rickhelmus/patRoon")

Error: JSON: EXPECTED value GOT <
In addition: Warning message:
In structure(xx, class = c("POSIXct", "POSIXt"), tzone = tz) :
Calling 'structure(NULL, *)' is deprecated, as NULL cannot have attributes.
Consider 'structure(list(), *)' instead.

It doesn't depend on the package I want to install, same error for different packages.

What does this error mean? and how can I fix it?

I'm using R Studio Version 1.1.463 and R 3.4.4.

Thanks! Andrea

> session_info()
 version  R version 3.4.4 (2018-03-15)
 os       Windows >= 8 x64            
 system   x86_64, mingw32             
 ui       RStudio                     
 language (EN)                        
 collate  English_United Kingdom.1252 
 ctype    English_United Kingdom.1252 
 tz       Europe/Berlin               
 date     2018-12-06 ](url)

[mara]

Have you updated devtools recently? If not, you might try that.

[andreamizzi]

yes, I have, but it didn't help.