Not able to access the mongodb using pymongo from my nginx flask app

I am trying to host a simple web application built using flask web framework. I am not able to access the mongodb from within the application using the pymongo module. But this pymongo module works perfectly when I use it in a python terminal. I get a Internal Server error when I try to do it in the app but it works fine on a terminal. Is there anything I need to do to access the mongodb from my flask app? Thank You.