Spring integration / GCP PubSub : channel subscriber lost - spring

Question

Everything is mostly in the title.
I have a specific channel to send data to PubSub, using Spring integration and this information about GCP PubSub
I don't have any problem locally, or on the QA env.
But, in the prod, I have the following error :
org.springframework.messaging.MessageDeliveryException: failed to send Message to channel
'pubSubFlow.channel#1'; nested exception is java.lang.IllegalStateException: The [bean
'pubSubFlow.channel#1'; defined in: 'class path resource [fr/auchan/lark/tracking/api/v1
/pubsub/PubSubRequestIntegration.class]'; from source: 'bean method pubSubFlow'] doesn't
have subscribers to accept messages
org.springframework.integration.support.utils.IntegrationUtils.wrapInDeliveryExceptionIfNecessary(IntegrationUtils.java:167) ~[spring-integration-core-5.3.5.RELEASE.jar:5.3.5.RELEASE]
org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:600) ~[spring-integration-core-5.3.5.RELEASE.jar:5.3.5.RELEASE]
org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:520) ~[spring-integration-core-5.3.5.RELEASE.jar:5.3.5.RELEASE]
org.springframework.integration.channel.FluxMessageChannel.lambda$subscribeTo$2(FluxMessageChannel.java:83) ~[spring-integration-core-5.3.5.RELEASE.jar:5.3.5.RELEASE]
reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onNext(FluxPeekFuseable.java:189) ~[reactor-core-3.3.13.RELEASE.jar:3.3.13.RELEASE]
reactor.core.publisher.FluxPublishOn$PublishOnSubscriber.runAsync(FluxPublishOn.java:439) ~[reactor-core-3.3.13.RELEASE.jar:3.3.13.RELEASE]
reactor.core.publisher.FluxPublishOn$PublishOnSubscriber.run(FluxPublishOn.java:526) ~[reactor-core-3.3.13.RELEASE.jar:3.3.13.RELEASE]
reactor.core.scheduler.WorkerTask.call(WorkerTask.java:84) ~[reactor-core-3.3.13.RELEASE.jar:3.3.13.RELEASE]
reactor.core.scheduler.WorkerTask.call(WorkerTask.java:37) ~[reactor-core-3.3.13.RELEASE.jar:3.3.13.RELEASE]
java.base/java.util.concurrent.FutureTask.run(Unknown Source) ~[na:na]
java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source) ~[na:na]
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) ~[na:na]
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) ~[na:na]
java.base/java.lang.Thread.run(Unknown Source) ~[na:na]
Caused by: java.lang.IllegalStateException: The [bean 'pubSubFlow.channel#1'; defined in: 'class path resource [PubSubRequestIntegration.class]'; from source: 'bean method pubSubFlow'] doesn't have subscribers to accept messages
org.springframework.util.Assert.state(Assert.java:97) ~[spring-core-5.2.12.RELEASE.jar:5.2.12.RELEASE]
org.springframework.integration.channel.FluxMessageChannel.doSend(FluxMessageChannel.java:61) ~[spring-integration-core-5.3.5.RELEASE.jar:5.3.5.RELEASE]
org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:570) ~[spring-integration-core-5.3.5.RELEASE.jar:5.3.5.RELEASE]
12 common frames omitted
Below is my channel declaration, and the use of ServiceActivator as written is the PubSub Guidelines (see the link above).
#Bean
public MessageChannel dataChannel() {
return MessageChannels.publishSubscribe(Executors.newCachedThreadPool()).get();
}
#Bean
public MessageChannel pubSubChannel() {
return MessageChannels.publishSubscribe(Executors.newCachedThreadPool()).get();
}
#Bean
public IntegrationFlow pubSubFlow(
MessageChannel dataChannel,
MessageChannel pubSubChannel) {
return IntegrationFlows
.from(dataChannel)
.fluxTransform(this::toPubSubFormat)
.channel(pubSubChannel)
.get();
}
#Bean
#ServiceActivator(inputChannel = "pubSubChannel")
public PubSubMessageHandler sendToPubSub(PubSubTemplate pubSubTemplate) {
PubSubMessageHandler adapter = new PubSubMessageHandler(pubSubTemplate,
pubSubIntegrationProperties.getTopic());
adapter.setPublishCallback(
new ListenableFutureCallback<>() {
#Override
public void onFailure(Throwable throwable) {
log.warn("There was the following error sending the message. " + throwable);
}
#Override
public void onSuccess(String result) {
log.debug("Message was sent via the outbound channel adapter to {} : {}", pubSubIntegrationProperties.getTopic(), result);
}
});
return adapter;
}
Did I miss something? Why is the pubSubChannel marked as having no subscribers?
Thanks for the help