rstudio – R studio no longer allowing me to download / install packages

Cant install packages

> install.packages("tidyverse")
Warning in install.packages :
  unable to access index for repository http://cran.rstudio.com/src/contrib:
  cannot open URL 'http://cran.rstudio.com/src/contrib/PACKAGES'

this is what i have tried so far

i have tried using a CRAN repository closer to me (im in sydney australia) – this didnt help
i have tried downloading rtools42 – didnt help
i have unchecked the box in packages “use secure download method for http”
i have even tried using an external repository

options(repos=c(cran=”http://cran.rstudio.com”))
and then tried to install.packages
but that still didnt help

I really am not sure what to do