Error during startup

> shiny::runApp("image_data_explorer.R", host = "0.0.0.0", port = 5476)
Loading required package: shiny
Installing devtools
Installing BiocManager
Installing shinyFiles
Installing shinycssloaders
Installing shinydashboard
Installing shinyWidgets
Installing shinybusy
Installing RANN
Installing uwot

Error in contrib.url(repos, "source") : 
  trying to use CRAN without setting a mirror
Calls: <Anonymous> ... ..stacktraceon.. -> install.packages -> contrib.url
Execution halted

@heriche any ideas?