Based on a search I did on your error message, it appears that this is simply a problem finding/locating the SQL Server name you've replaced the original value with:
Sounds like you have a basic connectivity issue that doesn't actually have much to do with Tableau?
Thank you for your response. I have double checked the SQL credentials and I could open the report out side the server, but when trying to open the report in the prod server I am getting this error. Do I need to check with my SQL admin???
It sounds like you’re not even getting to SQL Server from Tableau Server.
You might try installing Tableau Desktop or some other tool (Excel) on the Tableau Server and make sure that you can connect to this particular SQL Server from the box at all. Can you ping the SQL Server from the Tableau Server, for example? Can you telnet into the port that your SQL instance is running on from Tableau Server?