> For the complete documentation index, see [llms.txt](https://help.security.gallagher.com/knowledge-hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.security.gallagher.com/knowledge-hub/products/cc-software/troubleshoot/command-centre-errors/command-centre-errors-error-occurr-2.md).

# Error occurred while trying to establish communication with the SQL Server

[Command Centre - Errors](/knowledge-hub/products/cc-software/troubleshoot/command-centre-errors.md) › Error occurred while trying to establish communication with the SQL Server on this computer

**Error:** "An error occurred while trying to establish communication with the SQL Server on this computer. Please ensure that SQL Server is operational."

Causes include the SQL service not running, database permissions, or database corruption.

![Error: communication with the SQL Server could not be established](https://328339335-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F6bM8WhlBE9BYizPWJaPN%2Fuploads%2Fgit-blob-1c97cab785a94834c4aed56958450b076fb8545b%2FSECHUB-CCS-ERR-SQL-COMMS-01.png?alt=media)

## Resolution

| Location         | Resolution                                                                                                                                                                                 |
| ---------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| Command Prompt   | Test a SQL connection as an administrator: `sqlcmd -S .\gallagher`, then `use ccftcentral` (or `use cftevent` to check the event database), then `select * from single values`, then `go`. |
| Windows Services | Check the user account the SQL instance runs under has not changed. This can happen during an upgrade of the SQL instance during a Command Centre upgrade, in rare circumstances.          |

![Windows Services showing the SQL instance user account](https://328339335-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F6bM8WhlBE9BYizPWJaPN%2Fuploads%2Fgit-blob-c7e103799851f8c4ab34378b89c0a677ad626427%2FSECHUB-CCS-ERR-SQL-COMMS-02.png?alt=media)

***

🔗 **Related**

* [Databases - An Overview of Command Centre and SQL](/knowledge-hub/products/cc-software/configure/databases-an-overview-of-command-centr.md). SQLCMD connection test and service accounts.
* [Command Centre - Errors - Backup Not Working](/knowledge-hub/products/cc-software/troubleshoot/command-centre-errors/command-centre-errors-backup-not-worki.md). Another SQL connection fault after a server rename.


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