Open Port 1433 in Windows Firewall with Advanced Security

To open SQL port 1433 (or any port you configured) to enable SharePoint 2013 to communicate with SQL Server you need to do the following :

1. Login to SQL Server
2. Open Windows Firewall with Advanced Security
3. In Inbound Rules .. Click New Rule
4. Choose Port option and click Next
5. Choose TCP option and insert the port (1433) and then click Next
6. Choose Allow the connection option and click Next
7. Only Check Domain option and click Next
8. Inset a Name for the rule like 'SQL Server' and click Finish