> 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/000001812.md).
# Troubleshooting a Remote Server Returned An Error on NextSeq 500/550
The following error can occur at the start or during a run but will not cause the run to stop.
"Remote server returned an error: (426) Connection closed; transfer aborted"
This error is suspected to be caused by a temporary interruption in the network. Data transfer is expected to be resumed as soon as connection is restored.
**Troubleshooting steps:**
* If run has not stopped, allow instrument to proceed with sequencing and confirm all files are transferred successfully to the output location.
* If files were not transferred successfully to the output location, contact [Illumina Technical Support](https://www.illumina.com/company/contact-us.html#/united-states/technical-support) for further assistance.
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| *For any feedback or questions regarding this article (Illumina Knowledge Article #1812), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000001812%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |
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