Elatsic cache - redis - Not able to connect after writing ~30-40 K keys- connection pool issue

I am using Elastic cache redis with 4 shards and 2 replica nodes for each shard, in total 12 nodes. I am using spring data redis with lettuce. Below is my configuration for cluster connection -

public LettuceConnectionFactory redisConnectionFactory() {

    List<String>  nodes = new ArrayList<>();

    nodes.add("shard1***");
    nodes.add("shard2***");
    nodes.add("shard3***");
    nodes.add("shard4***");
    RedisClusterConfiguration clusterConfiguration = new RedisClusterConfiguration(nodes);
    return new LettuceConnectionFactory(clusterConfiguration);

}

I am writing data in a pipeline, which execute 5 write commands in a pipeline. Throughput is very high for this ~300K/per sec and due to this I am getting below error. Is there any way I can optimize lettuce pool to resolve this issue. Any pointer will be helpful.

at io.lettuce.core.LettuceFutures.awaitAll(LettuceFutures.java:88) Caused by: io.lettuce.core.RedisException: io.lettuce.core.RedisConnectionException: Unable to connect to 172.26.25.141:6379

at org.springframework.data.redis.connection.lettuce.LettuceConnection.closePipeline(LettuceConnection.java:542)
... 35 more

Caused by: io.lettuce.core.RedisConnectionException: Unable to connect to 172.26.25.141:6379 Caused by: io.lettuce.core.RedisConnectionException: Unable to connect to 172.26.25.141:6379

at io.lettuce.core.RedisConnectionException.create(RedisConnectionException.java:78)
at io.lettuce.core.RedisConnectionException.create(RedisConnectionException.java:56)
at io.lettuce.core.cluster.PooledClusterConnectionProvider.lambda$getConnectionAsync$6(PooledClusterConnectionProvider.java:384)
at java.base/java.util.concurrent.CompletableFuture.uniHandle(CompletableFuture.java:930)
at java.base/java.util.concurrent.CompletableFuture$UniHandle.tryFire(CompletableFuture.java:907)
at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506)
at java.base/java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:2088)
at io.lettuce.core.AbstractRedisClient.lambda$initializeChannelAsync0$4(AbstractRedisClient.java:329)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:577)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:551)