SQL error 53: Named Pipes Provider: Could not open a connection to SQL Server[53] during Solution Manager Managed System Configuration

I created SQL server login(PRD_SAPMonitor) in SQL server 2012(SAP Note 1458291 - SolMan 7.1 Database Warehouse & Alerting for MSSQL

).

Creating a SQL Server login.

These instructions are for SQL Server 2008. Other releases are very similar.

1. NOTE: This login must be created in the target SQL Server instance that you want to monitor. If your SolMan system runs on SQL Server, do *not* create this login in the local SolMan system.
2. In SQL Server Management Studio, open Object Explorer and expand the folder of the server instance in which to create the new login.
3. First make sure the SQL Server is configured for SQL Server authentication. Right-click on the server, choose Properties and then click on Security. Choose "SQL Server and Windows Authentication mode". Click OK.
4. Right-click the Security folder, point to New, and then click Login.
5. On the General page, enter a name for the new login in the Login name box.
6. Select SQL Server Authentication and enter a password for the login. Select the password policy options that should be applied to the new login.
7. Choose the database you want to monitor as the default database.
8. Choose the Server Roles page and check "sysadmin".
9. Choose the User Mapping page and select the database you want to monitor and select the db_owner role membership for the database.
10. Click OK.

I am able to login using PRD_SAPMonitor(SQL Authentication) in SQL Server 2012

Then, I setup DBA Cockpit in Manage System Config.

But I encounter below error:

SQL error 53: Named Pipes Provider: Could not open a connection to SQL Server[53]

Please help.

Regards,

Fadzly Iqbal