大家好~请问下，在安装ggplot的时候，运行
install.packages("ggplot2")
library(ggplot2)，报错，应该怎么解决？谢谢！！！


报错如下：
Warning in install.packages :
  unable to access index for repository https://cran.rstudio.com/src/contrib:
  cannot open URL 'https://cran.rstudio.com/src/contrib/PACKAGES'
将程序包安装入‘C:/Users/lenovolenovo/Documents/R/win-library/4.1’
(因为‘lib’没有被指定)
Warning in install.packages :
  unable to access index for repository https://cran.rstudio.com/src/contrib:
  cannot open URL 'https://cran.rstudio.com/src/contrib/PACKAGES'
Warning in install.packages :
  package ‘ggplot2’ is not available for this version of R


A version of this package for your version of R might be available elsewhere,
see the ideas at
https://cran.r-project.org/doc/manuals/r-patched/R-admin.html#Installing-packages
Warning in install.packages :
  unable to access index for repository https://cran.rstudio.com/bin/windows/contrib/4.1:
  cannot open URL 'https://cran.rstudio.com/bin/windows/contrib/4.1/PACKAGES'