SQL Server 2012 Express connection error

Question

I installed SQL Server 2012 but not able to connection to express instance getting below error:

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) (Microsoft SQL Server, Error: -1)

SQL Server is attempting to register a Service Principal Name (SPN) for the SQL Server service. Kerberos authentication will not be possible until a SPN is registered for the SQL Server service. This is an informational message. No user action is required. 2012-07-20 11:37:08.72 Server The SQL Server Network Interface library could not register the Service Principal Name (SPN) [ MSSQLSvc/VIPUL-MEHTA.XXXX.com ] for the SQL Server service. Windows return code: 0x2098, state: 15. Failure to register a SPN might cause integrated authentication to use NTLM instead of Kerberos. This is an informational message. Further action is only required if Kerberos authentication is required by authentication policies and if the SPN has not been manually registered.

Here is my SQL Server Configuration settings

In management studio I am providing below information to connect:

Server: .\MSSQLSERVER Authentication: Windows Authentication

In SQL Server 2012 how can I change the settings of Surface Area Configuration. I forgot the password for SA, so I cannot connect using SQL Server authentication.

Here is TCP IP Settings:

Answer 1

re-installing SQL was the only solution in my case. Learning is always attach 2-3 windows account with SQL Server.

Answer 2

Just open incoming port 1433 in the Windows firewall for TCP access:

http://blogs.technet.com/b/danstolts/archive/2011/06/08/how-to-open-firewall-port-1433-for-sql-server-database-engine-for-use-with-scom-or-anything-else.aspx

Answer 3

I just had this problem solved by following this guy's answer

Can't connect to localhost on SQL Server Express 2012 / 2016

Answer 4

In my case, SqlServer Service was somehow stopped,i think it's because after installing MySql.I changed back it's state to 'Running', and it works now:

• Go To Sql Server Configuration Manager
• Click on 'Sql Server Services' in the left pane

• Right click on the 'SQL Server' in the right pane and click on 'Start'

  http://i.stack.imgur.com/ZuTV3.png