Disconnected from server : shinyserver

Hello Everyone,
While running a shiny app , deployed on shinyserver within docker, facing a specific problem.One of the processing and plot rendering within app, takes around 17 mins on Rstudio (for large dataset ~ 1 million). But the same graph is not plotted on shinyapp running on shinyserver. browser shows "Disconnected from the server" after around 15 mins. There is no error printed in logs or browser's javascript console. Do I need to configure something on shiny sever. Any inputs to resolve or debug the issue , is much appreciated.

Details :
base Image : rocker/shiny-verse:4.0.4