What the framework is telling you, is that you are not setting the Aggregate Identifier in your Aggregate after the Aggregate-creation-event has been published.
You are thus likely missing an @EventSourcingHandler annotated method for an Aggregate creation event handler entirely.
Or, you’ve missed the @AggregateIdentifier annotation on the field you state is the aggregate’s identifier.
After typing the above, I checked your repository.
The issue is that you’re using the
@TargetAggregateIdentifier in your
InvoiceAggregate instead of the
If you change the annotation to the latter, the problem should be resolved.