GPT-4.1 intermittently retries with providerfault-model-no-response, causing 5–7 second pauses
C
CustomWeb AI
We are seeing intermittent latency spikes on a Vapi assistant using OpenAI GPT-4.1 with BYOK.
Example call ID:
01a0851d-6dea-7aab-877d-134166a7b932
Timestamp: 2026-09-09
The call logs show seven conversational first-attempt failures with:
providerfault-model-no-response
attemptNumber: 1
totalAttempts: 2
byok: true
Examples:
- Turn 42: first attempt failed at 07:43:28.832 UTC; first token arrived at 07:43:32.616 UTC — 5.327 seconds.
- Turn 53: first attempt failed at 07:44:35.661 UTC; first token arrived at 07:44:41.764 UTC — 7.299 seconds.
- Turn 56 also failed once and retried, with 7.192 seconds to first token.
The retry logs switch between gpt-4.1 and gpt-4.1-2025-04-14. The request uses temperature 0.3, max_tokens 400, and prompt_cache_retention 24h.
Please investigate:
- What upstream condition produces providerfault-model-no-response?
- Why does the retry switch between the model alias and dated snapshot?
- Are timeout or streaming issues contributing to the delay?
- Can you provide the underlying provider response or request IDs?
Vapi’s own logs show prompt caching is working, so this report concerns the failed requests and retries rather than caching.