Use CRAN without setting a mirror

Question

I am trying to knit a report template to produce an html doc but I get the following error: |................................... | 67% [unnamed-chunk-1]

processing file: ReportTemplate-1.Rmd

Quitting from lines 65-115 [unnamed-chunk-1] (ReportTemplate-1.Rmd)

Error in contrib.url(): ! trying to use CRAN without setting a mirror Backtrace:

1. utils::install.packages("tidyverse")
2. utils::contrib.url(repos, "source") Execution halted

I am trying to knit a report template and was expecting to receive an html doc