Setting up MS SSRS with Cloudflare - Error 1000

Hello Cloudflare Community,
I’m reaching out for insights or suggestions regarding an issue I’ve encountered while setting up Microsoft SSRS with Cloudflare’s Zero Trust.
Despite following the setup procedures, I am consistently facing a 1000 Forbidden IP error, and I’m currently at a loss on how to resolve it.

Here’s a brief overview of my setup:
SSRS is hosted on a Windows server machine, situated behind a firewall.
It uses username and password authentication, specifically for users in a designated Active Directory (AD) group.

My setup steps were as follows:
I successfully set up the Cloudflare tunnel, and received confirmation that it’s operational.
I then removed the DNS records from the zone.
Subsequently, I configured the application with a predefined list of emails for user access.

The issue arises post-login. Users can authenticate via their email, but immediately after this, the 1000 Forbidden IP Address error is triggered.
Has anyone here experienced a similar issue or have insights on setting up SSRS with Cloudflare Zero Trust? Any guidance on troubleshooting this error would be immensely appreciated.
I’m eager to learn from your experiences and solutions as inam on my initial steps with Cloudflare.
Thank you in advance for your assistance!