Lagom microservice is not able to form cluster due to Akka Sharding

I have a Lagom microservice, running on Kubernetes with 3 PODs. It is not able to form a cluster on startup and keeps on displaying the following message:

2019-07-12T19:29:27.310Z WARN akka.cluster.sharding.ShardRegion - Trying to register to coordinator at [ActorSelection[Anchor(akka.tcp://[email protected]:10001/), Path(/system/sharding/MicroserviceEventProcessorCoordinator/singleton/coordinator)]], but no acknowledgement. Total [1580] buffered messages. [Coordinator [Member(address = akka.tcp://[email protected]:10001, status = Up)] is reachable.]

Also the number of buffered messages is constantly increasing. Since there is no documentation for such behavior of a Lagom microservice, can anyone help me in understanding and fixing this issue?

Solution

I was not able to find a definitive answer to this issue. But following configurations solved the issue:

sharding.state-store-mode = ddata

and

serialization-bindings {
    "akka.Done" = akka-misc
    "akka.actor.Address" = akka-misc
    "akka.remote.UniqueAddress" = akka-misc
}

Now Akka Cluster Shards are not persisted in Event Store.