Check server name, host name, instance name, and etc. on SQL server .
SELECT HOST_NAME() AS 'host_name()',
@@servername AS 'ServerName\InstanceName',
SERVERPROPERTY('servername') AS 'ServerName',
SERVERPROPERTY('machinename') AS 'Windows_Name',
SERVERPROPERTY('ComputerNamePhysicalNetBIOS') AS 'NetBIOS_Name',
SERVERPROPERTY('instanceName') AS 'InstanceName',
SERVERPROPERTY('IsClustered') AS 'IsClustered'