Basic example fails and no valid themes are recognized on Windows

[aminadibi]

I am recently having trouble running shiny apps with any themes on Windows 10 and 11 using R version 4.1.2 and RStudio 2022.02.0 Build 443.

Here's the most basic reproducible example:

library(shiny)
library(shinythemes)

# Define UI for application that draws a histogram
ui <- fluidPage(theme = shinytheme("united"),

    # Application title
    titlePanel("Old Faithful Geyser Data"),

    # Sidebar with a slider input for number of bins
    sidebarLayout(
        sidebarPanel(
            sliderInput("bins",
                        "Number of bins:",
                        min = 1,
                        max = 50,
                        value = 30)
        ),

        # Show a plot of the generated distribution
        mainPanel(
           plotOutput("distPlot")
        )
    )
)

server <- function(input, output) {

    output$distPlot <- renderPlot({
        # generate bins based on input$bins from ui.R
        x    <- faithful[, 2]
        bins <- seq(min(x), max(x), length.out = input$bins + 1)

        # draw the histogram with the specified number of bins
        hist(x, breaks = bins, col = 'darkgray', border = 'white')
    })
}

shinyApp(ui = ui, server = server)

It doesn't work with any themes and gives me this error:

> runApp()
 Error in shinytheme("united") : united is not an available theme. Valid themes are: .

I have tried this on different machines with different operating systems. I have this issue in Windows 10 and 11, but not in Mac or Ubuntu. On Windows 10, manually deleting and reinstalling the package did not help.

Here's session info:

> sessionInfo()
R version 4.1.2 (2021-11-01)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 19044)

Matrix products: default

locale:
[1] LC_COLLATE=English_United States.1252 
[2] LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] shinythemes_1.2.0 shiny_1.7.1      

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.8       withr_2.5.0      digest_0.6.29    later_1.3.0     
 [5] mime_0.12        R6_2.5.1         lifecycle_1.0.1  xtable_1.8-4    
 [9] magrittr_2.0.2   rlang_1.0.1      cli_3.2.0        promises_1.2.0.1
[13] ellipsis_0.3.2   tools_4.1.2      httpuv_1.6.5     fastmap_1.1.0   
[17] compiler_4.1.2   htmltools_0.5.2