Foundary Tools Document Intelligence FormRecognizer, Internal Server Error.

Question

Foundary Tools Document Intelligence FormRecognizer, Internal Server Error.

Matias Haller 0

Today we suddendly experience the following error:

(InternalServerError) An unexpected error occurred. Code: InternalServerError Message: An unexpected error occurred. Exception Details: (FailedToSerializeAnalyzeResult) Failed to serialize analyze results, please contact support. Code: FailedToSerializeAnalyzeResult Message: Failed to serialize analyze results, please contact support. {"$type":"System.Exception, System.Private.CoreLib","ClassName":"System.Exception","Message":" RecoverableAzureError: Document Intelligence poller.result failed: (InternalServerError) An unexpected error occurred.\nCode: InternalServerError\nMessage: An unexpected error occurred.\nException Details:\t(FailedToSerializeAnalyzeResult) Failed to serialize analyze results, please contact support.\n\tCode: FailedToSerializeAnalyzeResult\n\tMessage: Failed to serialize analyze results, please contact support.","Data":null,"InnerException":{"$type":"Microsoft.Azure.WebJobs.Script.Workers.Rpc.RpcException, Microsoft.Azure.WebJobs.Script","IsUserException":false,"RemoteStackTrace":"Traceback (most recent call last):\n File "/home/site/wwwroot/.python_packages/lib/site-packages/azure/core/polling/base_polling.py", line 788, in run\n self._poll()\n File "/home/site/wwwroot/.python_packages/lib/site-packages/azure/core/polling/base_polling.py", line 820, in _poll\n raise OperationFailed("Operation failed or canceled")\nazure.core.polling.base_polling.OperationFailed: Operation failed or canceled\n\nThe above exception was the direct cause of the following exception:\n\nTraceback (most recent call last)

We have:
Pricing tier: Standard

In the metrics no error is shown, we did not make any changes in the code and Azure Health is OK for this resource.

Can you please advice with action to take?

Thank you
Matias

Karnam Venkata Rajeswari 3,255 Reputation points Microsoft External Staff Moderator

2026-05-27T23:40:12.38+00:00
Hello @Matias Haller ,

Welcome to Microsoft Q&A .Thank you for reaching out to us.

Thank you for sharing the detailed error context and observations.

The reported behavior—InternalServerError with FailedToSerializeAnalyzeResult, occurring without any application changes and not reflected in metrics or service health signals—indicates that the request is successfully accepted and processed by Azure AI Document Intelligence. However, the failure occurs during the final response construction stage, specifically while serializing the analyzed result before returning it to the caller.

This pattern aligns with a transient service-side condition affecting the result serialization layer.

The issue has now been mitigated on the service side, and normal operation has been restored.

Please retry the same request or batch - a successful completion is expected after retry.

Please check if the following additionally help as mitigation step if encountered similar scenarios-

Applying retry with exponential backoff To handle transient 5xx-class failures Retry on:

HTTP 500 InternalServerError

OperationFailed exceptions

Suggested backoff pattern:

2s > 5s > 10s > 20s -use jitter if possible

Ensure retry logic is applied to the long-running operation (polling flow), not just the initial submission

. Retrying result retrieval In some cases, the operation completes internally but fails during result fetch:

Perform a single retry of the result retrieval step

This often resolves serialization-stage failures

The following references might be helpful , please check them out

Use Document Intelligence client library or REST API - Foundry Tools | Microsoft Learn

What Is Azure Document Intelligence in Foundry Tools? - Foundry Tools | Microsoft Learn

Please let us know if the response was helpful

Thank you
Matias Haller 0 Reputation points

2026-05-28T10:15:55.63+00:00

Hello Karnam,

Thanks for responding

We still getting this error, InternalServerError / FailedToSerializeAnalyzeResult, te strange thing is that in Document AI Metric we dont see any errors.

This was working fine the pas 3 month. Please let me know about your findings we retray several batches and we still have this issue and we can not process our batches.

Thank you!
Matias
Karnam Venkata Rajeswari 3,255 Reputation points Microsoft External Staff Moderator

2026-05-28T20:35:29.18+00:00

Hello @Matias Haller ,

Following up to see if the above response was helpful

Thank you

1 answer

Your answer

Karnam Venkata Rajeswari 3,255 Reputation points Microsoft External Staff Moderator

2026-05-27T23:40:12.38+00:00

Hello @Matias Haller ,

Welcome to Microsoft Q&A .Thank you for reaching out to us.

Thank you for sharing the detailed error context and observations.

The reported behavior—InternalServerError with FailedToSerializeAnalyzeResult, occurring without any application changes and not reflected in metrics or service health signals—indicates that the request is successfully accepted and processed by Azure AI Document Intelligence. However, the failure occurs during the final response construction stage, specifically while serializing the analyzed result before returning it to the caller.

This pattern aligns with a transient service-side condition affecting the result serialization layer.

The issue has now been mitigated on the service side, and normal operation has been restored.

Please retry the same request or batch - a successful completion is expected after retry.

Please check if the following additionally help as mitigation step if encountered similar scenarios-

Applying retry with exponential backoff To handle transient 5xx-class failures Retry on:

HTTP 500 InternalServerError

OperationFailed exceptions

Suggested backoff pattern:

2s > 5s > 10s > 20s -use jitter if possible

Ensure retry logic is applied to the long-running operation (polling flow), not just the initial submission

. Retrying result retrieval In some cases, the operation completes internally but fails during result fetch:

Perform a single retry of the result retrieval step

This often resolves serialization-stage failures

The following references might be helpful , please check them out

Use Document Intelligence client library or REST API - Foundry Tools | Microsoft Learn

What Is Azure Document Intelligence in Foundry Tools? - Foundry Tools | Microsoft Learn

Please let us know if the response was helpful

Thank you
Matias Haller 0 Reputation points

2026-05-28T10:15:55.63+00:00

Hello Karnam,

Thanks for responding

We still getting this error, InternalServerError / FailedToSerializeAnalyzeResult, te strange thing is that in Document AI Metric we dont see any errors.

This was working fine the pas 3 month. Please let me know about your findings we retray several batches and we still have this issue and we can not process our batches.

Thank you!
Matias
Karnam Venkata Rajeswari 3,255 Reputation points Microsoft External Staff Moderator

2026-05-28T20:35:29.18+00:00

Hello @Matias Haller ,

Following up to see if the above response was helpful

Thank you

Answer 1

kagiyama yutaka 3,430

I think this InternalServerError / FailedToSerializeAnalyzeResult is a service‑side 5xx and the next step is to retry and send the failed requestId, time, and region to Azure Support.

Matias Haller 0 Reputation points

2026-05-28T10:12:32.4766667+00:00

.

We still getting this error, InternalServerError / FailedToSerializeAnalyzeResult

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Foundary Tools Document Intelligence FormRecognizer, Internal Server Error.

1 answer

Your answer