# 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"
**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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