Not Able to connect JDBC: SQL Server Database

While Connecting sql server database getting below ERROR - 

Can't get the Connection for specified properties; com.microsoft.sqlserver.jdbc.SQLServerException: Cannot open server "IN-QA16" requested by the login. The login failed..

I am Using below Information- 

Driver:  com.microsoft.sqlserver.jdbc.SQLServerDriver

Connection String: jdbc:sqlserver://HOST;databaseName=QA123;user=QAtest;password=QApassword

NOTE - I am not using PORT No.

If any correction required in Connection String Please do correct and update same in comments.

Please give me solution ASAP.

Thanks

Kumar Prakash