[Bug] OpenCode Go — "Request blocked by upstream provider" (HTTP 401) on all models despite active subscription

Description

I have an active OpenCode Go subscription, but all API requests to /chat/completions are being rejected with:
{"type":"error","error":{"type":"AuthError","message":"Request blocked by upstream provider."}}

`
HTTP Status: 401

This affects all models (DeepSeek, GLM, Qwen, Kimi) on both the Go (/zen/go/v1) and Zen (/zen/v1) endpoints. The issue has persisted for multiple days.

Environment

• OS: macOS
• App: OpenCode Desktop (/Applications/OpenCode.app) — Electron
• Subscription: OpenCode Go (active, usage at 0%)
• Account: jcastillovnz@gmail.com
• API Key (last 4 chars): Z22l (newly generated on 2026-07-27)

Steps to Reproduce

1. Open OpenCode or run a curl request against the Go endpoint.
2. Send any chat/completion request to any model.
3. Receive HTTP 401 with AuthError: Request blocked by upstream provider.

Plugins
None (clean config — only $schema and shell defined in opencode.jsonc)
OpenCode version
1.18.7
Steps to reproduce

1. Open OpenCode Desktop (v1.18.7) or run a curl request against the Go endpoint.
2. Send any chat/completion request to any model (tested: deepseek-v4-flash, glm-5, qwen3.6-plus, kimi-k2.7-code).
3. Receive HTTP 401 with: {"type":"error","error":{"type":"AuthError","message":"Request blocked by upstream provider."}}
   Curl reproduction command:
   curl -s -w "\nHTTP: %{http_code}" "https://opencode.ai/zen/go/v1/chat/completions"
   -H "Authorization: Bearer sk-u9TS...Z22l"
   -H "Content-Type: application/json"
   -d '{"model":"deepseek-v4-flash","messages":[{"role":"user","content":"hi"}],"stream":false}'
   Key finding: GET /models returns HTTP 200 (key is valid), but POST /chat/completions returns HTTP 401 (blocked).
   Two different API Keys tested with the same result — this is an account-level block, not a key issue.
   Related issues: #38218, #38216, #38190, #38257
   Screenshot and/or share link

N/A — Error is in API response, not UI. Full log excerpt:
timestamp=2026-07-27T23:28:08.897Z level=ERROR providerID=opencode-go modelID=deepseek-v4-flash error.error="AI_APICallError: Request blocked by upstream provider."
Operating System
macOS 26.5.2 (Build 25F84)
Terminal
zsh (default macOS terminal)