Hi @vinayprakash808,
I'm not familiar with the protoDash package, but the error "[function] is not an exported object from [package]" usually means that you are trying to run a function that R can't find in the packages that you have loaded.
It's a little hard to tell what's going on from the code you posted, and it might help if you could provide a small example of your app. But I'm going to take a guess that the function you meant to use is runApp, in the shiny package. Try replacing run_app with runApp in your app and see if the code runs then?