Unable to connect SQL server to create WSUS Database

While installing WSUS role, I select option to install WSUS Database, so it prompted to mention the server name, since my SQL database is running in different machine, i continued to mention the correct Sqlserver name /instance name , but resulted in below error. Most of the blogs I referred diverted me to wrong option.


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: 25 - Connection string is not valid)

This error happens because of any of the below reason

1. Right SQL server name is not mentioned

2. Firewall blocks the remote SQL connection

3. SQL service is not running



I verified SQL service and server name and didn’t find any issue, so to narrow down the issue, I switched off the firewall of SQL server and tried to connect the SQLserver and instance name, but didn’t get success :)
Finally just mentioned the SQL server name, instead of SQLserver/instance name and tried.
It worked like a charmJ.. Good luck for you guys.