Black Lives Matter. Please consider donating to Black Girls Code today.

Plotly sankey on shinyapps.io (R) does not show node labels on Firefox

This is a rather weird issue: So I’ve developed a web app using R Shiny including a lot of plotly graphs and now deployed it to shinyapps.io. Everything is fine except that the plotly sankey I include does not render the nodes’ labels on Firefox (tested it on Ubuntu and Windows) on shinyapps io, when I run it locally it works like a charm and shows the labels like it’s supposed to (also on Firefox).

Do you have any idea what the issue might be?

Here is a reproducible example that works fine locally or on a shiny server but not on shinyapps .io (I published it to https://matflow.shinyapps.io/sankey-example/ ).

library(shiny)
library(plotly)

ui <- fluidPage(
  plotly::plotlyOutput("sankey")
)

server <- function(input, output) {
  
  output$sankey <- plotly::renderPlotly({
    
    # example from plot ly /r/sankey-diagram/#style-sankey-diagram
    p <- plot_ly(
      type = "sankey",
      orientation = "h",
      
      node = list(
        label = c("A1", "A2", "B1", "B2", "C1", "C2"),
        color = c("blue", "blue", "blue", "blue", "blue", "blue"),
        pad = 15,
        thickness = 20,
        line = list(
          color = "black",
          width = 0.5
        )
      ),
      
      link = list(
        source = c(0,1,0,2,3,3),
        target = c(2,3,3,4,4,5),
        value =  c(8,4,2,8,4,2)
      )
    ) %>% 
      layout(
        title = "Basic Sankey Diagram",
        font = list(
          size = 10
        )
      )
    
    p
  })
}

shinyApp(ui = ui, server = server)

Thank you in advance,
Jakob