TCP Connection between akka cluster nodes

akkaVersion =‘2.6.21’

two hosts containing two akka jvms which are supposed to be clustering is not working due to the following error seen in

seed-node error log running in linux machine:

2025-06-03 23:43:11,209 WARN a.s.Materializer [Grid-akka.actor.default-dispatcher-33] [outbound connection to [akka://Grid@WUPWAP98A0123.ENT.ORG.CORP:45004], message stream] Upstream failed, 
cause: StreamTcpException: Tcp command [Connect(WUPWAP98A0123.ENT.ORG.CORP/<unresolved>:45004,None,List(),Some(5000 milliseconds),true)] failed 
because of akka.io.TcpOutgoingConnection$$anon$2: Connect timeout of Some(5000 milliseconds) expired

windows machine log trying to join seed node, I see that the node received a init join ack form the seed node but has outbound connection errors to secondary seed node and all other nodes in the cluster and keeps crashing after some time since they quanrantine it.

[akka://Grid@WUPWAP98A0123.ENT.ORG.CORP:45004] - Received InitJoinAck message from [Actor[akka://Grid@seednodeLinuxHost.org.com:45000/system/cluster/core/daemon#330545871]] to [akka://Grid@WUPWAP98A0123.ENT.ORG.CORP:45004]
2025-06-03 23:41:51,259 INFO a.c.Cluster [Grid-akka.actor.default-dispatcher-19] Cluster Node [akka://Grid@WUPWAP98A0123.ENT.ORG.CORP:45004] - Welcome from [akka://Grid@seednodeLinuxHost.org.com:45000]
2025-06-03 23:42:11,466 INFO a.r.RemoteActorRefProvider$RemoteDeadLetterActorRef [Grid-akka.actor.default-dispatcher-35] Message [akka.cluster.GossipEnvelope] from Actor[akka://Grid/system/cluster/core/daemon#-172957024] to Actor[akka://Grid/deadLetters] was not delivered. [1] dead letters encountered. If this is not an expected behavior then Actor[akka://Grid/deadLetters] may have terminated unexpectedly. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
2025-06-03 23:42:11,471 WARN a.s.Materializer [Grid-akka.actor.default-dispatcher-35] [outbound connection to [akka://Grid@seednodeLinuxHost2.org.com:50173], message stream] Upstream failed, cause: OutboundHandshake$HandshakeTimeoutException: Handshake with [akka://Grid@seednodeLinuxHost2.org.com:50173] did not complete within 20000 ms

I suspect this line :
cause: StreamTcpException: Tcp command [Connect(WUPWAP98A0123.ENT.ORG.CORP/<unresolved>:45004,None,List(),Some(5000 milliseconds),true)] failed

the" unresolved" is the culprit but I dont know what causes this and what can be done to fix this, can anyone help with this?