new topic

Author: LauraBrenner

articles/batch/batch-retry-after-errors.md

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+---
+title: Retrying tasks after an error
+description: Check for errors and retry them.
+services: batch
+documentationcenter: .net
+author: LauraBrenner
+manager: evansma
+editor: ''
+tags: azure-batch
+
+ms.assetid: 16279b23-60ff-4b16-b308-5de000e4c028
+ms.service: batch
+ms.topic: article
+ms.tgt_pltfrm: 
+ms.workload: big-compute
+ms.date: 02/15/2020
+ms.author: labrenne
+ms.custom: seodec18
+---
+
+# Detecting errors 
+
+It is important to remember to check for errors when working with a REST service API. It isn't uncommon for errors to occur when running batch jobs.
+
+## Common errors 
+
+- Networking failures which means the request never reached Batch or the Batch response didn't reach the client in time.
+- Internal server errors which is a standard 5xx status code HTTP response.
+- Throttling can cause errors such as 429 or 503 status code HTTP responses with the Retry-after header. 
+- 4xx errors which include such errors as AlreadyExists and InvalidOperation. This means that the resource is not in the correct state for the state transition requested by the customer. 
+
+## When to retry
+
+The Batch APIs will notify you if there is a failure. They can all be retried and include a global retry handler for that purpose. It is best to use this built-in mechanism.
+
+After a failure, you should wait a bit (several seconds between retries) before retrying. If you retry too frequently or too quickly, you will be throttled. This is managed by the retry handler.
+
+
+For detailed information about each API and their default retry policies, read [Batch Status and Error Codes](https://docs.microsoft.com/rest/api/batchservice/batch-status-and-error-codes).