I published a simple .NET 6.0 web app with user authentication on my IIS 10.0 web server hosted on Azure.  

The application read and write data from a SQL Server 2017 database hosted on another machine on the same virtual network of the web server.

Everything works fine but after a while, even though nobody is using the app, it stop working and send Http Error 503 Service Unavailable and I have to restart it every time from the application pool.

I enabled tracing on the event log, but I don't receive any message explaining this.

These are the application settings:
[IIS application settings](https://i.stack.imgur.com/VE3ZC.png)

I tried to follow these advices but none of them worked:

* [IIS HTTP Error 503. The service is unavailable](https://stackoverflow.com/questions/66700502/iis-http-error-503-the-service-is-unavailable)
* [503 “Service Unavailable” error for all apps after installing .NET Core 2.2 Runtime & Hosting Bundle for Windows](https://stackoverflow.com/questions/54899577/503-service-unavailable-error-for-all-apps-after-installing-net-core-2-2-runt)
* [.Net core Service Unavailable after Publish to IIS](https://stackoverflow.com/questions/54665323/net-core-service-unavailable-after-publish-to-iis)

On the same web server I have other applications but this problem appears only on this one. None of the other apps is using .NET 6, most use .NET Framework 4.7/4.8 and another couple .NET Core 3.1.

I also tried to publish the application on Azure WebApp service and it has the same problem.