Error:18456, Severity:14, State:58 in SQLServer

Users may encounter SQL Server login failures with below error message.

Cannot connect to “SQL Server\Instance”
Additional Information:
Login failed for user “TestUser”.(Microsoft SQL Server, Error: 18456) 

User is able to connect using Windows credentials, but not able to connect using “SQL Server Authentication” using SQL Server Management Studio and ODBC.

Let’s see what is in the ERROR.LOG

2014-01-28 23:06:46.80 Logon     Error: 18456, Severity: 14, State: 58.
2014-01-28 23:06:46.80 Logon      Login failed for user TestDB. Reason: An attempt to login using SQL authentication failed. Server is configured for Windows authentication only. [CLIENT: xx.xx.xx.xx]

Cause: The server is configured for Windows authentication only and not able to connect using SQL Server Authentication.

Solution: Modify the Server is to use both SQL Server and Windows Authentication mode.

Right Click on Instance -- Go to properties -- Click on security – change to “SQL Server and Windows Authentication mode” – Restart the Instance

After SQL Server instance restart you should be able to connect. Sometimes users may see below error

provider: SQL Network Interfaces, error: 28- Server doesn’t support requested protocol) (Microsoft SQL Server 

Follow the below link to resolve the issue
http://www.sqlserver-expert.com/2014/01/cannot-connect-to-sql-server-or-instance.html

Thanks,
Satishbabu Gunukula
http://www.sqlserver-expert.com