Hi Sid,
I ran into the same issue a couple weeks ago. What error are you getting in your logs? For me it was in 7.13.1, and I kept receiving a time out error.
After searching around I found this.
https://forum.mendix.com/link/questions/90517
Hope this helps!
This how-to explains how you can work with images and files with Mendix. Out of the box Mendix supports uploading of files and images. It also allows you to view images and download files that you uploaded. First you need to create your own domain model and define which entities are images and which are files. This is done by the concept of ‘inheritance’, sometimes called ‘generalization’. By inheriting from ‘System.Image’ your own entity gets all the properties of the system image entity. This means that you can use the standard platform widgets to upload and view images. The same goes for file documents.