> For the complete documentation index, see [llms.txt](https://knowledge.illumina.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://knowledge.illumina.com/instrumentation/nextseq-500-550/instrumentation-nextseq-500-550-troubleshooting-list/000003265.md).

# Troubleshooting a Flow Cell Door error on the NextSeq 500/550

The following error can appear during initialization or when setting up a sequencing run or wash. This can be a communication error, especially if the instrument had not been power cycled in a while.

**Error message**: "Exception generated from IxCmdIllumina.Spark.EmbeddedCommandSet.ix\_dlowcell\_door\_open : An error has occurred while executing command Originally caused by: An error has occurred while executing the command"

![](/files/lglfiQwBnpUD4Lqeor1S)

**Troubleshooting steps:**

1. Power cycle the NextSeq 500/550.
2. If instrument initializes without errors, the door can be tested as follows:
   1. Navigate to **Manage Instrument** and select **Unload Consumables**.
   2. Proceed with the wash setup.

* If the error does not re-appear, the instrument is cleared for continued use.
* If the error is recurring, contact [Illumina Technical Support](https://www.illumina.com/company/contact-us.html#/).

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #3265), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000003265%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |


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