# Failing TLS handshake between OpenTelemetry and ElasticSearch using ES CA Cert

**URL:** https://discuss.elastic.co/t/failing-tls-handshake-between-opentelemetry-and-elasticsearch-using-es-ca-cert/345596
**Category:** Elastic Observability
**Tags:** elastic-stack-alerting, docker
**Created:** [October 23, 2023, 8:26pm UTC](https://discuss.elastic.co/t/failing-tls-handshake-between-opentelemetry-and-elasticsearch-using-es-ca-cert/345596 "2023-10-23T20:26:28Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![vsabado](https://avatars.discourse-cdn.com/v4/letter/v/f6c823/32.png) [@vsabado](https://discuss.elastic.co/u/vsabado)
#### Post date: [October 23, 2023, 8:26pm UTC](https://discuss.elastic.co/t/failing-tls-handshake-between-opentelemetry-and-elasticsearch-using-es-ca-cert/345596/1 "2023-10-23T20:26:28Z")

</div>

I downloaded the CA cert for Elastic Search from the security page. I ran the command curl -v --cacert "ESCert.crt" "myESEndpoint" and verified connection just fine.

When I configure my OpenTelemetry collector config:

exporters:  
logging:  
verbosity: detailed  
otlp/elastic:  
endpoint: myESEndpoint  
headers:  
Authorization: secretToken  
tls:  
insecure: false  
ca\_file: "myESCert.crt"

I'm getting this error:

"rpc error: code = Unavailable desc = connection error: desc = "transport: authentication handshake failed: x509: certificate signed by unknown authority""

I'm not sure why curl would work but not the connection from the collector to ES. Any ideas?