Deploy web app to Azure but still showing Microsoft page instead

Question

I'm trying to deploy my web app to Microsoft Azure and everything goes fine in visual studio. But when it launches it shows:

Hey, App Service developers!
Your app service is up and running.
Time to take the next step and deploy your code.

How can I show my web page instead of this page?

Here is the output I get in Visual Studio.

------ Publish started: Project: RCMania, Configuration: Debug Any CPU ------
Transformed Web.config using C:\DDAC\Assignment\RCMania\RCMania\Web.Debug.config into C:\Users\Admin\AppData\Local\Temp\WebSitePublish\RCMania-1747672403\obj\Debug\TransformWebConfig\transformed\Web.config.
Auto ConnectionString Transformed C:\Users\Admin\AppData\Local\Temp\WebSitePublish\RCMania-1747672403\obj\Debug\TransformWebConfig\transformed\Web.config into C:\Users\Admin\AppData\Local\Temp\WebSitePublish\RCMania-1747672403\obj\Debug\CSAutoParameterize\transformed\Web.config.
Copying all files to temporary location below for package/publish:
C:\Users\Admin\AppData\Local\Temp\WebSitePublish\RCMania-1747672403\obj\Debug\Package\PackageTmp.
Start Web Deploy Publish the Application/package to https://rcmania.scm.azurewebsites.net/msdeploy.axd?site=rcmania ...
Adding ACLs for path (rcmania)
Adding ACLs for path (rcmania)
Updating file (rcmania\Web.config).
Adding ACLs for path (rcmania)
Adding ACLs for path (rcmania)
Publish Succeeded.
Web App was published successfully http://rcmania.azurewebsites.net/
========== Build: 1 succeeded or up-to-date, 0 failed, 0 skipped ==========
========== Publish: 1 succeeded, 0 failed, 0 skipped ==========

Answer 1

In my case the app was failing to start up due to an unhandled exception thrown in my startup code.

However, the reason it was difficult to diagnose is it wasn't shown in the logs in the "log stream" section of the Azure portal. (this is using linux with ASP.NET core 3.1)

When I used the SSH console, went into the /home/LogFiles directory I could see log messages saying what had gone wrong.

Answer 2

The last time i had an issue like this is was because of the Default Documents. Make sure you default page is listed in here and is above hostingstart.html