We run a set of NestJS microservices that talk to each other over Azure Service Bus queues. For a while, our error handling assumption was simple and wrong: "if the consumer throws, the message just gets redelivered." What really happened, a transient downstream failure would silently drop a message. Queue Message Drops Table of Contents The failure mode Azure Service Bus will redeliver a message if your handler throws and you don’t complete it but only up to maxDeliveryCount