System.Net.Tests.HttpListenerAuthenticationTests fail with UnexpectedFailure #135190

Running assembly:System.Net.HttpListener.Tests, Version=11.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51
[FAIL] System.Net.Tests.HttpListenerAuthenticationTests.ExtendedProtectionSelectorDelegate_IncreasesPolicyBetweenNtlmLegs_AuthenticationFails
Assert.Equal() Failure: Values differ
Expected: Unauthorized
Actual:   UnexpectedFailure
   at System.Net.Tests.HttpListenerAuthenticationTests.ExtendedProtectionSelectorDelegate_IncreasesPolicyBetweenNtlmLegs_AuthenticationFails() in /_/src/libraries/System.Net.HttpListener/tests/HttpListenerAuthenticationTests.cs:line 273

Build Information

Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1622350
Build error leg or test failing: System.Net.Tests.HttpListenerAuthenticationTests.ExtendedProtectionSelectorDelegate_IncreasesPolicyBetweenNtlmLegs_AuthenticationFails
Pull request: https://github.com/dotnet/runtime.git/pull/135172

Error Message

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Fill the error message using step by step known issues guidance.

{
  "ErrorMessage": ["HttpListenerAuthenticationTests","UnexpectedFailure"],
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1622350
Error message validated: [HttpListenerAuthenticationTests UnexpectedFailure]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 10/4/2026 6:14:52 PM UTC

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