Hi @prabhat Tunuguntla ,
1.This may be a network communication problem, your application cannot connect to the database engine. Check your firewall for any blocked settings. You could try turning off the Microsoft Windows Firewall, restarting, and see if that works. Of course, there may be many such cases. For details, you could start with SQL for detailed investigation.
2.If the SharePoint_Config database is missing, you could refer to this article: Regarding the SharePoint_Config database is missing.
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