Getting ??? symbols instead of special characters when rendering HTML in shiny R

Question

When I open my html file in a browser everything renders fine but when I run the shiny app I am getting a ? symbol where certain characters should be. For example the ' symbol returns this in my index page: app?s

What I want: app's

library(shiny)

ui <- fluidPage(
  uiOutput("html")
)

server <- function(input, output, session) {
  output$html <- renderUI({
    tags$iframe(style = "height:800px; width:100%; scrolling=yes", src = "www/index.html")
  })
}

shinyApp(ui, server)

Answer 1

I figured out my mistake. The html file had originally been converted from a word document and the encoding was not UTF-8 compatible with R. I simply changed the encoding to UTF-8 and everything works!