There is an option called WdbcTimeZone which stores information about the timeZone for the instance. The delivery template might be referencing this option through the <% include option> directive and if this is populated with a value not present in the timezone enum , it might throw an error like you are seeing.
You may add a new enum but it's not recommended to do it directly in the OOB schema. If you need it indeed , you should extend the schema.Else , you can go for the already defined enum of Australia/Canberra
You are using incorrect timezone in your delivery to set contactDateTimeZone, maybe you have some custom typology to assign the value or incorrect value for the delivery operator timezone or server timezone.
Allowed values are for Australia are
either update the timezone to correct value or update the "xtk:common:timezone" enum with one additional value.