Azure Document Intelligence - Model Training - InternalServerError: An unexpected error occurred.

Question

Azure Document Intelligence - Model Training - InternalServerError: An unexpected error occurred.

Dean Parker 21

We are trying to train a Document Intelligence Model in Azure Document Intelligence Studio.

In the past it has worked fine, but now if we try and Train a model we just see this:

InternalServerError: An unexpected error occurred.

There is no other information. What should we do in this situation? Do we need a support ticket or is there any way for customers to see why Model Training does not work?

Anshika Varshney 13,405 Reputation points Microsoft External Staff Moderator

2026-06-03T10:19:09.9533333+00:00

Hello @Dean Parker

Did you get any chance to review the response.

Thankyou!
Dean Parker 21 Reputation points

2026-06-03T14:25:59.44+00:00

Hi @Anshika Varshney

Yes thank you every much. I reduced the documents in the training down to 5 for each category (the minimum needed) and it worked fine.

Hopefully Microsoft can change this in the future to show a better error message as otherwise without your help customers have no idea why it doesn't work.

Thanks!
Anshika Varshney 13,405 Reputation points Microsoft External Staff Moderator

2026-06-03T14:59:29.3266667+00:00

Hi @Dean Parker

Thank you for sharing the update I appreciate you taking the time to confirm the resolution!

Since I’ve converted comment into an answer, could you please take a moment to mark it as Accepted?

This helps others in the community with the same question find the solution more easily.

Thankyou!

Answer accepted by question author

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Anshika Varshney 13,405 Reputation points Microsoft External Staff Moderator

2026-06-03T10:19:09.9533333+00:00

Hello @Dean Parker

Did you get any chance to review the response.

Thankyou!
Dean Parker 21 Reputation points

2026-06-03T14:25:59.44+00:00

Hi @Anshika Varshney

Yes thank you every much. I reduced the documents in the training down to 5 for each category (the minimum needed) and it worked fine.

Hopefully Microsoft can change this in the future to show a better error message as otherwise without your help customers have no idea why it doesn't work.

Thanks!
Anshika Varshney 13,405 Reputation points Microsoft External Staff Moderator

2026-06-03T14:59:29.3266667+00:00

Hi @Dean Parker

Thank you for sharing the update I appreciate you taking the time to confirm the resolution!

Since I’ve converted comment into an answer, could you please take a moment to mark it as Accepted?

This helps others in the community with the same question find the solution more easily.

Thankyou!

Answer 1

Hello @Dean Parker

The InternalServerError: An unexpected error occurred during Azure Document Intelligence custom model training is a known issue with several root causes.

Step-by-Step Troubleshooting

Check Training Data Limits (Most Common Cause)

Your training dataset exceeds the allowed limits

RequirementCustom Extraction Model--------Max Pages500 pages totalMax Size50 MB for all files combinedFile TypesPDF, JPEG, PNG only [stackoverflow]Action: Reduce your training dataset to ≤500 pages and ≤50 MB total.

Check Input File Requirements

Password-protected PDFs → Not supported
Encrypted files → Remove encryption
Corrupted/malformed files → Test with clean documents
Overly scanned or high-DPI images → Can slow processing

Action: Test with a small, clean document first (under 5 MB, 10 pages).[stackoverflow]

Verify Labels.json Alignment

Misaligned labels in your training data is a frequent cause:

Ensure labels.json matches your document filenames exactly
Check that all labeled fields exist in the document
Verify no duplicate or conflicting labels

Customer-Managed Keys (CMK) Issue

If using Azure Key Vault for encryption:

Verify the Document Intelligence service has proper Key Vault access permissions
Temporarily switch to Microsoft-managed keys to isolate encryption-related problems

Try a Different Azure Region

Some users reported regional instability causing this error. Try deploying your resource in a different region.

Train a New Model (Not Update Existing)

Metadata conflicts can occur when updating existing models:

Train a new model with a fresh model ID instead of updating

Check Your Tier

F0 (Free tier) has strict limitations and may fail with larger datasets
S0 (Pay-As-You-Go) is recommended for custom model training

Hope this helps! Let me know which step resolves your issue. Do let me know if you have any further querieds.
Thankyou!

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Azure Document Intelligence - Model Training - InternalServerError: An unexpected error occurred.

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