Shiny server crashes when using modalDialog()

Hi-

Using the RStudio modalDialog example, I can run this locally but cannot run it on shiny-server (I tried deploying to shinyapps.io, my own local server, and Amazon EC2 instance).

I also made sure to add "library(shiny)" to the script and to sudo install shiny package.

Every in the browser is the same:
"An error has occurred

The application failed to start.

The application exited during initialization."

While the error in the log (/var/log/shiny-server) states that:

Warning message:
replacing previous import by ‘Rcpp::evalCpp’ when loading ‘later’
Error in func(fname, ...) : app.R did not return a shiny.appobj object.
Calls: runApp -> -> appObj -> func
Execution halted

Is there something that needs to be modified in that script to enable it to be deployed?

It seems that the modification is not returning a shiny.app object.

Hi, can you post the script that you are using? The page you are referring to contains multiple examples.
The problem might be that the if ( interactive() ) {} is in the script

Yep, it was the interactive function. Just curious, what's the purpose of that function in the demos?