The shiny package will not load after installation

Question

I tried:

install.packages('shiny')
library(shiny)

Got the following message:

Error: package or namespace load failed for ‘shiny’ in loadNamespace(i, c(lib.loc, .libPaths()), versionCheck = vI[[i]]): there is no package called ‘htmltools’ In addition: Warning message: package ‘shiny’ was built under R version 4.0.5

I tried starting over and loading htmltools and then also the following error:

Error in library(htmltools) : there is no package called 'htmltools'