Hello I am getting inconsistent webhook errors both on Assistant Request, Status Update, and End Of Call Report. They are 500 errors, and are responding with timeouts of 7500 ms and 20000 ms. In the past the call.in-progress.error-vapifault-custom-llm-llm-failed error has been because our service was taking too long to return the llm response, but after digging into our logs I am seeing that these invocations aren't being made on to our service. My assumption is there is something going wrong with VAPI calling our endpoint. On top of this I've tried to replicate the issue by calling our endpoints via postman concurrenlty and received no timeouts. I've listed a few call ids and and full example with our logs below. It seemed to start around 4 pm yesterday. This is very urgent as we are losing business. Please any assistance would be great. Call ids: 96400d2d-338f-4178-a95d-f4444e326328 621336e3-249d-4c7a-a30d-16b5644d53d3 @Shubham Bajaj

Thank you for sharing the details and call IDs. To help narrow down the cause of these 500 webhook errors, could you confirm if you have recently changed any server URL or authentication settings (such as secret tokens, custom headers, or OAuth2 credentials) in your Vapi configuration? This will help determine if the issue is related to endpoint configuration or if further investigation into Vapi's delivery is needed. If you need immediate assistance, you can also reach out to Vapi support at [support@vapi.ai](support@vapi.ai) or join the [Discord community](https://discord.com/invite/pUFNcf2WmH) for real-time help. Sources: - [Vapi Server URL documentation](https://docs.vapi.ai/server-url) - [Vapi Server Authentication documentation](https://docs.vapi.ai/server-url/server-authentication) - [Vapi Server Events documentation](https://docs.vapi.ai/server-url/events) - [Vapi Discord support thread](https://discord.com/channels/1211482211119796234/1372358449761091584) - [Vapi Support page](https://docs.vapi.ai/support)

It started around 06 Jun 2025: 4:08 PM

Looking into it

@Kings_big💫 please let me know if you need anything else, I’ll add a loom video shortly to explain further. Thank you!!

Hi @slickVik I an away from my keyboard I will take a look into your issue later.

Thank you @Shubham Bajaj

Looking at the VAPI webhook logs for the specific call IDs you have provided, here's what's actually happening: Call ID: 621336e3-249d-4c7a-a30d-16b5644d53d3 (June 6, 18:18 UTC) - **Assistant Request**: 7.5-second timeout → "timeout of 7500ms exceeded" - **Status Update**: 20-second timeout → "timeout of 20000ms exceeded" Call ID: 96400d2d-338f-4178-a95d-f4444e326328 (June 6, 18:18 UTC) - **Assistant Request**: 7.5-second timeout → "timeout of 7500ms exceeded" - **Status Update**: 0.31 seconds → 200 Success Call ID: 68c6b5bf-1872-49e3-84c6-2505319557b2 (June 6, 23:50 UTC) - **Assistant Request**: 0.33 seconds → 200 Success - **End Of Call Report**: 0.38 seconds → 200 Success The data reveals this is NOT a VAPI webhook delivery failure. VAPI is successfully making HTTP requests to , but the Azure Functions endpoint is intermittently slow or unresponsive. Key Evidence: 1. **Exact timeout values**: 7500ms and 20000ms are configured timeout thresholds 2. **Inconsistent response times**: Some calls respond in 0.3s, others timeout completely 3. Pattern suggests Azure Functions cold starts or performance issues 4. All timeouts return HTTP 500 from customer's endpoint

@Shubham Bajaj thanks for the help, we are investigating it.

Let me know what do you found, and If I can help you further.

@slickVik did you resolve? running into something similar

Hey Matt, we actaully migrated away from VAPI.

moved since you couldn't resolve this or something else?

check your DM.