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Emanuele Bartolesi
Emanuele Bartolesi

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Fix Blazor WebAssembly authorization bug on Azure

Today I wasted more or less 2 hours for a stupid bug on a Blazor WASM hosted on ASP.NET Core app.
As always, it works on my machine.

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I have created an application secure with Azure AD (and roles) and I use it for debugging for one month, without any issues.
When I tried to deployed everything on our test application on Azure, after the login, I obtained always the error: Failed to load resource: the server responded with a status of 400 (Bad Request)
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At the beginning I thought that it was my fault because I recreated the App Registration from scratch before the deployment.
After an hard googling session, I found an issue on GitHub on the ASP.NET Core repository:


  • Edit the Client project file (double click on the project from Visual Studio 2022) and add the following lines:
        <TrimmerRootAssembly Include="Microsoft.Authentication.WebAssembly.Msal" />
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  • Delete all the "bin" and "obj" folders from the Server and App projects (manually)

  • Deploy the solution again and check the flag "Remove additional files at destination"

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Enjoy your app with the Azure authentication :)

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