TLS handshake timeout with Splunk Observability Cloud

[Eshwar]

Hello Community,

I am setting up a OpenTelemetr Application with in the docker on-prem environment  as per steps which are outlined in the below documentation.

https://lantern.splunk.com/Observability/Product_Tips/Observability_Cloud/Setting_up_the_OpenTelemet...

However, Otel Collector throws below errors while connecting to ingestion URL. 

tag=otel-collector 2025-07-24T12:49:17.841Z info internal/retry_sender.go:133 Exporting failed. Will retry the request after interval. {"resource": {"service.instance.id": "45be9d90-2946-4ae4-8cd9-f0edff3bc822", "service.name": "otelcol", "service.version": "v0.129.0"}, "otelcol.component.id": "otlphttp", "otelcol.component.kind": "exporter", "otelcol.signal": "traces", "error": "failed to make an HTTP request: Post \"https://ingest.us1.signalfx.com/v2/trace/otlp\": net/http: TLS handshake timeout", "interval": "27.272487507s"}

and I tried with curl and it hang while checking TLS

[root@kyn-app-01 opentelemetry-demo]# curl -v https://api.us1.signalfx.com/v2/apm/correlate/host.name/test/service \
-X PUT \
-H "X-SF-TOKEN: accesstoken" \
-H "Content-Type: application/json" \
-d '{"value": "test"}'
* Trying 54.203.64.116:443...
* Connected to api.us1.signalfx.com (54.203.64.116) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* CAfile: /etc/pki/tls/certs/ca-bundle.crt
* TLSv1.0 (OUT), TLS header, Certificate Status (22):
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* OpenSSL SSL_connect: Connection reset by peer in connection to api.us1.signalfx.com:443
* Closing connection 0
curl: (35) OpenSSL SSL_connect: Connection reset by peer in connection to api.us1.signalfx.com:443

So, kindly suggest what went wrong and how to fix it.

Note: Firewall is disabled and no proxy.

Regards,

Eshwar

[livehybrid]

Hi @Eshwar 

I know you mentioned the firewall is disabled, but I wanted to check - is there any corporate firewall/proxy in place (which is often transparent) between your host and the internet? Ive seen this error countless times with firewalls blocking the traffic, even when no firewall is on the host itself. 

Another issue could possibly be ciphers - What OS are you running? Is it relatively modern and up to date? 

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