Standalone Blazor WASM with Azure Static App causes net::ERR_HTTP2_PROTOCOL_ERROR

[apsthisdev]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

.NET 6 Standalone Blazor WASM deployed on Azure Static Apps causes first-time load errors in Firefox, Chrome, and Edge. Next, load correctly and loads the app.

I can consistently reproduce the issue in Chrome Incognito mode. But the error comes when I clear all the cache and load the app the first time on regular tab (the error is random, but it comes frequently).

Test App: https://black-moss-05a44c41e.1.azurestaticapps.net

Google Chrome

Firefox

Expected Behavior

The app should load correctly first time and subsequent time as well.

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

6.0.300

Anything else?

VS 2022

[javiercn]

@ameyasubhedar thanks for contacting us.

I'm trying the url you provided but I'm not able to reproduce the issue. How often does this happen? Would you be able to capture a network trace using wireshark or a similar tool so that we can see if there is something happening at the TCP level?

[apsthisdev]

@javiercn, the issue is random but I can reproduce frequently, especially in incognito mode and after clearing the cache.

I have the wireshark trace, how do I share it with you. GitHub does not allow the file.

Here is the network log from chrome, its complaining about CORS and Http2 error But I don't call make any API .
black-moss-05a44c41e.1.azurestaticapps.net.log
black-moss-05a44c41e.1.azurestaticapps.net-1655386663639.log

[javiercn]

@ameyasubhedar can you file the issue through Visual Studio report a problem and attach the files there? Just paste the link to the issue here. https://docs.microsoft.com/en-us/visualstudio/ide/how-to-report-a-problem-with-visual-studio?view=vs-2022

[apsthisdev]

@javiercn, even the VS report does not allow wireshark file extension. I just renamed the extension and uploaded here...

Please rename to .*pcapng

[javiercn]

@ameyasubhedar I was suggesting using VS because it allows to share it privately. You shouldn't share pcapng files in the open as they might contain private information.

I've removed the link from your comment just in case.

[apsthisdev]

Ok thanks, Noted. So you have the data now for your debugging purposes ?

[javiercn]

@ameyasubhedar yep.

What I'm seeing is a LOT of network errors, which might explain the errors you are seeing

[apsthisdev]

Ok but they are specific to my test Blazor WASM on static app. I don't see these errors on any other sites.

[javiercn]

@ameyasubhedar Yes, but that might mean many things.

If there are issues with the network it can be anything between you and Azure that is causing the issue. Have you tried from a different machine/network?

[SteveSandersonMS]

@anthonychu Do you think someone on the Azure Static Web Apps team could look at this?

Blazor itself is just the files being served so it can't cause this HTTP2 protocol error as far as I understand. I don't know if there's an Azure Static Web Apps problem or not here, but I guess someone on that side would be best to look into that!

[apsthisdev]

@javiercn, I just tried a minor color change and redeployed to Azure and tested on a different machine. Got the same Http2 Error. The first time load gets stuck on

Console errors

After errors I hit F5 to refresh

This pattern is consistent, so this is definitely the first time load after change or in incognito mode without cache that causes the error.

[asperpint]

+1, I have been scratching my head from last 4 days and facing the same random load issue for our production apps. They started throwing random HTTP2 errors. The only change we made is that we upgraded to .NET 6.0.300 from .NET 6.0.201

Both our production apps have the same random errors (Build with Blazor WASM Standalone .NET6 and Deployed on Azure Static App).

1. https://www.perpetualintelligence.com/
2. https://consumer.perpetualintelligence.com/

@javiercn, The error is random and hitting F5 makes it go away. The typical sign of the error is it take a long time to load and then times out with Http2 error. There is no network interruption. I have verified that.

After Refresh on the same tab: