Azure Application Proxy Issue

Question

Hi Microsoft team,

I am Sreenivas Kaushik working for KMD Denmark.

We are planning to use Azure Application Proxy for accessing an On-Prem application (using Pre-Authentication as Passthrough) for one of our requirements. While we were working on Proof of Concept (POC) and tried to access the On Prem Web Application we got an error as GatewayTimeout: The corporate app cannot be accessed . Few months back, when we tried it was working fine.

Below are the different approaches we did and getting the same results.

• Created the M365 account to test the .net core MVC application on Windows 2019 and Windows 2022 Servers
• Created the Virtual Machine (Windows 2019) in Azure and created the .net core MVC application using M365 account
• Tried using port 80 with the default application from IIS
• Tried accessing the .net core MVC application using Pay-As-You-Go subscription and got the same error as mentioned above.

We would like to know is this the known issue? Is it that only we are facing this issue ? Could you please help us how we can resolve this issue?

Also we would like to know can we use Azure Application Proxy with .Net core Web API?

Please find the screenshot attached.

Thanks & Regards,

Sreenivas Kaushik