OTLP ingestion 401 error: “legacy auth cannot be upgraded because the host is not found”

Grafana Cloud
1

Hello Grafana team,

I’m on the free Grafana Cloud plan and trying to send OpenTelemetry metrics from my application to Grafana Cloud, but OTLP ingestion fails even with newly created Cloud Access Policy tokens.

Details:

  • Stack slug: sortafriends

  • Stack ID: 1346099 (from Instance Details)

  • Region / Zone: prod-us-west-0 (US West)

  • Org ID: 1508005

  • OTLP endpoint: https://otlp-gateway-prod-us-west-0.grafana.net/otlp/v1/metrics

  • Token type: glc_… Cloud Access Policy token with metrics:write scope (created via Administration → Users and access → Cloud access policies).

  • Error response (401):

{“status”:“error”,“error”:“authentication error: legacy auth cannot be upgraded because the host is not found”}

  • Grafana-Trace-Id: e.g. 33f2086989c451c59e8732ada7c2d89d (from response header)

What I’ve tried:

  • Confirmed the token is glc_… (not glsa_…) and includes metrics:write.

  • Decoded token metadata shows “m”:{“r”:“prod-us-west-0”} which matches my stack region.

  • Verified endpoint and header format:

Authorization: Bearer <glc_token>

  • Tested with curl against /otlp/v1/metrics → still 401.

  • Recreated multiple tokens — same issue.

Ask:

Could someone from the Grafana Cloud team check whether the OTLP gateway routing is correctly provisioned for my stack (1346099 in prod-us-west-0)? It looks like the tokens are valid but the gateway can’t associate them with the tenant.

Thanks in advance :folded_hands:

2

I recommend to open support ticket in your Grafana Cloud portal.

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