Acronis Backup can use either SQL Server Authentication or Windows Authentication to connect to a Microsoft SQL Server instance.
By default, Windows Authentication is used. This means that the software applies the credentials with which you are logged on to Windows, or the credentials you specify after the --host parameter in order to access a remote machine.
SQL Server Authentication is possible only if it is enabled in the instance properties. To connect to the instance by using SQL Server Authentication, specify the --credentials parameter after the --instance or --destination_instance parameter.