Hi @bibhusisa,
As you can see from the call to capabilities(), a number of the graphical capabilities aren't installed for your R instance, including png. It looks like you're using a Cloudera installation of R, which must have been compiled without those capabilities enabled. We generally recommend installing R from source to make sure all of the capabilities are properly compiled.
The easiest way to fix this problem is to reinstall R from source.
Instructions are doing so are here: https://docs.rstudio.com/connect/admin/getting-started.html#install-r (The process is the same for RStudio Server and RStudio Connect, and these instructions have been updated more recently).
After the configure step in the instructions, you should be able to see which capabilities are enabled so you can adjust system dependencies as might be needed.
Also, see this question for more help: Warning: Error in .External2: unable to start device PNG
Let us know how it goes!