audio file gives 416 Error when broser tries to download it in .net 9 (works in .net 8)

[gregoryagu]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

In a .net 9 Blazor Server App, this code results in a 416 error in the browser:

<audio controls="controls">
    <source src="/soundtest.mp3" type="audio/mpeg" />
</audio>

To reproduce, create a .net 9 Blazor Server App, add an audio file, and then add an audio element.

The file will play when served directly from the URL, so the file is in fact there on the server and available.

I have tried this in .net 8 and it works perfectly.

Expected Behavior

Audio file is played.

Steps To Reproduce

See above.

Exceptions (if any)

Audio should play.

.NET Version

9

Anything else?

Issue occurs in Visual Studio Dev , as well as published to Azure.

[javiercn]

@gregoryagu thanks for contacting us.

We have a PR #59325 to backport the fix we did on main in a future release