@Vij
Thank you for posting in Microsoft Q&A forum.
1.During our installation process, please help check the ConfigMgrSetup.log located in our C drive to see if there is any further information.
2.Which user account have we used to install our SCCM? Have we added the user account to SQL server administrators?
Here is a useful article for you to refer to:
installing-sql-server-2012-for-configuration-manager-2012-r2
Note: This is non-Microsoft article just for your reference.
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