FactorMineR package in R saying N/A for R 3.6.1 (R3.6.1 "Action of Toes" / using RStudio Version 1.2.5019 / Ubuntu 18.04.3) [duplicate]

I am using the same version of R and RStudio on Windows 10. The FactorMineR package installs and works fine.

However, same thing but on Ubuntu: Warning in install.packages : package ‘FactorMineR’ is not available (for R version 3.6.1)

Any idea what is going on? I am sort of new to R and Ubuntu. Thank you.