no one nodes with valid ssl session

[Riz vaughan]

Hello,
I have an environment of production with 50+ nodes. All the nodes send logs to a central server by td-agent and on the central server, td-agent collects those logs and send those to Elasticsearch.
The issue I am facing is that after some time(~6/7 hours), td-agent on the nodes stop sending logs to the central server. In the logs of td-agent I see the following.
"  2021-03-29 20:31:10 +0000 [warn]: #0 suppressed same stacktrace
2021-03-29 20:31:10 +0000 [warn]: #0 retry succeeded. chunk_id="5beb2c2855d94714d90bf8ec80aede33
2021-03-29 20:32:30 +0000 [warn]: #0 failed to flush the buffer. retry_time=0 next_retry_seconds=2021-03-29 20:32:31.604646018 +0000 chunk="5beb2c74bd60a90aa5890a6ae6132e84" error_class=RuntimeError error="no one nodes with valid ssl session"
These logs keep coming in and no logs are being sent to the central server untill I restart td-agent on the node. Only then I see the logs arriving in central server and then to elasticsearch. On internet there are few such cases but all are related to elasticsearch plugin but in this case, I am not sending logs to elasticsearch directly and there are no elasticsearch plugin running.
Could anybody help me understand what the issue is and how to resolve it?
Thank you

Config: 

<match ad-ss.tt**>

  type copy

  <store>

  type secure_forward

  secure true

  self_hostname ad-x.x.x-01

  shared_key xxxxxxxxxxxxx

  buffer_type file

  buffer_path /var/log/td-agent/buffer/forward

  flush_interval 10s

  num_threads 4

  retry_wait 10s

  ca_cert_path /etc/ssl/certs/ca_cert_kibana.pem

  <server>

        host xxxxxx

        port 24285

  </server>

</store>

  <store>

    type forest

    subtype s3

  <template>

    s3_bucket "xxxx"

    s3_region "eu-west-1"

    path xxxxx

    s3_object_key_format %{path}%{time_slice}_%{index}.%{file_extension}

    time_slice_format ${tag}/YEAR=%Y/MONTH=%m/DAY=%d/HOSTNAME=${hostname}/HOUR=%H/%M

  <format>

    @type json

  </format>

    store_as gzip

  <buffer time>

    timekey 60

    @type file

    path /var/log/td-agent/buffer/s3/${tag}

    timekey_wait 1m

    chunk_limit_size 50m

    flush_at_shutdown true

  </buffer>

    </template>

   </store>

</match>

td-agent version 4

P.s I had a similar question, wanted to edit it and ended up deleting it. sorry.