SQL Server error 40 could not open a connection to sql server 2016

Error related are:
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I have covered this error in another post as well which is here.

Cause of Error:

This error occurs when the SQL Server can’t be found on Network which means either IP address is not reachable or that the TCP port number is either not open or is not the correct port number or is blocked by a firewall etc

Resolution:

Below steps will help troubleshoot these issues

 

1.Check if you can Ping the Server
2.Check if Firewall is open for Connectivity
3.Check if SQL Server Service and if named instance then Browser Service is Running
4.Check if TCP/IP is Enabled in SQL Server Configuration Manager
5.Check if SQL Server has “Allow Remote Connections” set in properties on Instance level

Additional information below:

For Default instance the TCP/IP port used is 1433 but this can be changed manaully. So please check TCP IP port is still level at default 1433