Getting UnavailableShardsException when setting the password for "elastic" user - elasticsearch

Question

On AWS EC2, I have deployed an Elasticsearch cluster. I have added the following setting to the "elasticsearch.yml" file in order to create a password for the "elastic" user:
xpack.security.enabled: true
The complete elasticsearch.yml file is :
http.port: 9900
xpack.ml.enabled: false
xpack.security.enabled: true
network.host: [_local_, _site_]
path.data: /data/esdata
path.logs: /data/logs
xpack.security.transport.ssl.enabled: true
xpack.security.transport.ssl.verification_mode: certificate
xpack.security.transport.ssl.client_authentication: required
xpack.security.transport.ssl.keystore.path: elastic-certificates.p12
cluster.name: es-cluster
node.name: node1
node.roles: [ "master" ]
cluster.initial_master_nodes:
- node1
discovery.seed_hosts:
- 172.**.*.***:9300
Now, I am trying to set the password for the "elastic" user using the below command
./bin/elasticsearch-reset-password -u elastic
However, the moment I issue this command, the cluster enters the red status.
The logs are :
[2022-07-19T04:32:18,733][INFO ][o.e.x.s.a.f.FileUserPasswdStore] [node1] users file [/home/ubuntu/elasticsearch-8.3.2/config/users] changed. updating users...
[2022-07-19T04:32:18,736][INFO ][o.e.x.s.a.f.FileUserRolesStore] [node1] users roles file [/home/ubuntu/elasticsearch-8.3.2/config/users_roles] changed. updating users roles...
[2022-07-19T04:32:51,113][INFO ][o.e.x.s.s.SecurityIndexManager] [node1] security index does not exist, creating [.security-7] with alias [.security]
[2022-07-19T04:32:51,183][INFO ][o.e.c.m.MetadataCreateIndexService] [node1] [.security-7] creating index, cause [api], templates [], shards [1]/[0]
[2022-07-19T04:32:51,196][INFO ][o.e.c.r.a.AllocationService] [node1] current.health="RED" message="Cluster health status changed from [YELLOW] to [RED] (reason: [index [.security-7] created])." previous.health="YELLOW" reason="index [.security-7] created"
[2022-07-19T04:33:28,767][INFO ][o.e.x.s.a.f.FileUserPasswdStore] [node1] users file [/home/ubuntu/elasticsearch-8.3.2/config/users] changed. updating users...
[2022-07-19T04:33:28,769][INFO ][o.e.x.s.a.f.FileUserRolesStore] [node1] users roles file [/home/ubuntu/elasticsearch-8.3.2/config/users_roles] changed. updating users roles...
[2022-07-19T04:34:21,234][WARN ][r.suppressed ] [node1] path: /_security/user/elastic/_password, params: {pretty=, username=elastic}
org.elasticsearch.action.UnavailableShardsException: [.security-7][0] [1] shardIt, [0] active : Timeout waiting for [1m], request: indices:data/write/update
at org.elasticsearch.action.support.single.instance.TransportInstanceSingleOperationAction$AsyncSingleAction.retry(TransportInstanceSingleOperationAction.java:231) [elasticsearch-8.3.2.jar:?]
at org.elasticsearch.action.support.single.instance.TransportInstanceSingleOperationAction$AsyncSingleAction.doStart(TransportInstanceSingleOperationAction.java:181) [elasticsearch-8.3.2.jar:?]
at org.elasticsearch.action.support.single.instance.TransportInstanceSingleOperationAction$AsyncSingleAction$2.onTimeout(TransportInstanceSingleOperationAction.java:254) [elasticsearch-8.3.2.jar:?]
at org.elasticsearch.cluster.ClusterStateObserver$ContextPreservingListener.onTimeout(ClusterStateObserver.java:345) [elasticsearch-8.3.2.jar:?]
at org.elasticsearch.cluster.ClusterStateObserver$ObserverClusterStateListener.onTimeout(ClusterStateObserver.java:263) [elasticsearch-8.3.2.jar:?]
at org.elasticsearch.cluster.service.ClusterApplierService$NotifyTimeout.run(ClusterApplierService.java:649) [elasticsearch-8.3.2.jar:?]
at org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingRunnable.run(ThreadContext.java:710) [elasticsearch-8.3.2.jar:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) [?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) [?:?]
Connection to ec2-52-66-242-245.ap-south-1.compute.amazonaws.com closed by remote host.
Connection to ec2-52-66-242-245.ap-south-1.compute.amazonaws.com closed.
Can anyone please help me resolve this issue?