Error: TypeError Message: undefined is not an object (evaluating 'Bu.startsWith') Timestamp: 2025-09-12T01:14:06.339Z https://cdn.discordapp.com/attachments/1415868122279448627/1415868122933497866/Screenshot_2025-09-12_at_11.12.34_AM.png?ex=68c4c572&is=68c373f2&hm=78b1d13fadd98c78a22374c9b5e796b7e0bac88a0cd563fe671e11bce6e58f81&

Action Step: Since the error persists when switching to the gpt-4o cluster, please contact Vapi support for direct assistance. You can email support@vapi.ai or join the [Vapi Discord community](https://discord.com/invite/pUFNcf2WmH) for real-time help. Tip: Include the error message and a screenshot when reaching out to speed up troubleshooting. Source: - [Vapi Support](https://docs.vapi.ai/support)

Hi Ronan, If you're experiencing crashes when switching to the gpt-4o model, ensure you're specifying the model correctly in your configuration. According to the [October 8, 2024 changelog](https://docs.vapi.ai/changelog/2024/10/8), you should use

gpt-4o-2024-08-06

for Azure OpenAI. this appears to be related to concurrency and capacity management:** 1. Common Causes: - Exceeding organization's concurrent call limit - Too many simultaneous WebSocket connections - Backend resource constraints 2. How to Address: - Check your organization's concurrency limits - Space out call attempts (avoid sending too many at once) - Monitor active call count - Implement backoff strategies for retries 3. Best Practices: - Stagger outbound calls in smaller batches - Allow time between batches for system recovery - Monitor call success rates - Keep track of active calls If you're experiencing circuit overload: 1. Reduce concurrent call volume 2. Space out call attempts