Cannot Connect to SQL Server or Instance

Installed SQLServer with named instance and when trying to connect from remote host received following error

Cannot connect to “SQL Server\Instance”
Additional Information:
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: 28- Server doesn’t support requested protocol) (Microsoft SQL Server)

Error Screen shot: 

There are various reasons for this error, below are the main reasons

1. You might have entered an incorrect connection string – double check that the connection string is correct or not. If you are using the IP address to connect then make sure that you are able to ping the IP.

2. Instances /Server is down , not yet started- Check SQL Server , Agent, SQL Full-Text Filter Daemon Launcher, SQL Server Browser services are up and running. If not running start the services

3. Remote connection on the SQL Server Instance was not enabled

Right Click on SQServer Instance --> Properties -->Go to “Connections”--> “Allow remote connections to this server” should be checked

4. TCP/IP port is not enabled on the Instance

Open Microsoft SQL Server Configuration Manager--> SQL Server Network Configuration -->Protocols for “Instance”--> TCP/IP MUST be “Enabled”. If not ENABLE the same.

You should be able to connect now. If you are using the dynamic port 1433 make sure to change to Static port using below post/URL

http://www.sqlserver-expert.com/2012/07/configure-sqlserver-to-listen-on-static.html

Regards
Satishbabu Gunukula
http://www.sqlserver-expert.com