Redis containers suddenly closed

Question

I am setting up a redis cluster with 6 containers(Redis 7.2.5). After scanning with the scan command along with various test cases, I delete the keys I obtained. I'm using RedisPlusPlus. But suddenly the redis instances are shutting down. I don't know how a client can cause a server to shut down.

my cluster.conf is

cluster-enabled yes
cluster-config-file nodes.conf
databases 16
timeout 300
tcp-keepalive 60
maxmemory 2gb
maxmemory-policy allkeys-lru
cluster-node-timeout 15000
cluster-require-full-coverage yes
protected-mode no
dbfilename dump-rdb
dir /data
save 10 1
loglevel debug
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit replica 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60

When I examine the logs, I saw the interesting log below: I/O error reading from node link: connection closed I/O error reading from node link: connection closed Connection with Node ... at ... failed: Connection refused.

Those are the latest logs.

I'm working on a virtual machine. I could not find the cause of the problem.