Network-related or instance-specific errors when establishing a connection to SQL Server

Today, after configuring the MSSQL 2005 database backup job, an error occurred while running the job:

After searching for something that might be relevant to the MSSQL protocol and checking with the local configuration, and discovering that the Named Pipes protocol is not enabled locally, the following approach is used:

To enable remote connections on a SQL Server instance
1. Point to Start Program->microsoft SQL Server 2005-> Configuration tool->sql Server surface Area Configuration
2. On the SQL Server 2005 Surface Area Configuration page, click the surface area Configuration for services and connections
3. Then click to expand Database Engine, select Remote connection, and on the right, select Local Area Connection and remote connection.
Then select the protocol you want to use (this place should enable the TCP/IP and Named Pipes service!). Click "Apply" and you will see the following message:
"Changes made to the connection settings will not take effect until the Database engine service is restarted. , click the OK button to return
4. Expand Database Engine, select Services, click Stop on the right, and wait until the MSSQLSERVER service stops.
Then click Start to restart the MSSQLServer service.

Finally, the job is run again, and it can be backed up normally.

Reference:
Http://www.cnblogs.com/aiyp1314/archive/2011/07/19/2110950.html

Network-related or instance-specific errors when establishing a connection to SQL Server