Hi @Thibaut Fabrice ,
This error means that the website could not connect to the SQL Server instance. There are several possibilities on what is wrong.
I found a similar thread Microsoft SSMS displaying the following instance error, and I quote CathyJi-MSFT :
Please follow below steps to troubleshot this issue,
- Make sure SQL Server Service is running
- If a named instance, make sure SQL Server browser service is running. Make sure the instance name is spelled correct and there is actually such an instance on your target machine.
- Make sure SQL Server is configured to allow remote connections
- Examine the SQL Server error log for messages confirming that SQL is listening on the expected network interfaces and ports
- Test server connectivity with PING from the client machine
- Test port connectivity using TELNET to the server and port (from step 4) from the client machine. For example TELNET <server-name> 1433
- Check firewall settings if step 5 or 6 connectivity test fails
Kind regards,
Wilko
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