Hosting a multi-page dash application on IIS

I’m trying to host a multi-page dash application using Microsoft IIS. I have followed the instruction on this page URL Routing and Multiple Apps | Dash for Python Documentation | Plotly, and my application works fine both on the built-in test server and using Waitress. I have been encountering difficulty getting IIS to host it though. I believe the issue is that the entry point to the application and where the actual flask application are defined are different files. I have got both simple one page flask and dash applications running through IIS, just not a multi-page one. How would I solve this issue?

Cheers