没有名为＆＃39; gridExtra＆＃39;

Question

尝试在我的RStudio

上安装gridExtra时出现以下错误

install.packages('gridExtra')  - successfully installed
library(gridExtra) - not accessible error given below

Warning in install.packages :
  unable to access index for repository http://cran.rstudio.com/src/contrib:
  internet routines cannot be loaded
Warning in install.packages :
  unable to access index for repository http://cran.rstudio.com/src/contrib:
  internet routines cannot be loaded
Warning in install.packages :
  package 'gridExtra' is not available (for R version 3.4.1)
 Show Traceback
Error in library(gridExtra) : there is no package called 'gridExtra'