SCCM 2012 - Setup unable to connect to SQL Server with the connection infomation provided

1. Open SQL Server Configuration Manager
2. Expend SQL Server Network Configuration, select Protocols for MSSQLSERVER (instance name for sccm database).
3. Make sure TCP/IP Enable.

4. Right click on TCP/IP, select properties, make sure under IPAll, TCP Dynamic Ports is blank and TCP Port is correct.

5. Restart SQL server service.