### Answer Since you've already tried changing the LLM model and voice without resolution, and your other 30 agents work fine, this points to a configuration issue specific to this one agent rather than a platform-wide problem [(1) ]() . Based on the troubleshooting guidance, here are additional areas to check: Audio Quality Settings: - Review the

voice_temperature

,

voice_speed

, and

volume

settings for this agent [(2) ]() [(3) ]() [(4) ]() - Check if

enable_dynamic_voice_speed

is causing issues - try setting it to false - Verify the

voice_model

selection is appropriate for your chosen voice Noise and Acoustic Issues: - Check the

denoising_mode

setting - ensure it's set to

"noise-cancellation"

- Review if

ambient_sound

settings might be interfering with clarity Speech Recognition: - Verify the

language

setting matches your use case - Check

stt_mode

- try switching between

"fast"

and accurate modes - Review

custom_stt_config

if you're using a custom provider Latency-Related: - If responses are delayed or choppy, this could manifest as "garbled" audio [(1) ]() - Consider switching to a faster LLM or TTS if latency is the root cause Since this is affecting a live agent and standard troubleshooting hasn't resolved it, I recommend: - Visit [Documentation]() - Ask questions on [Discord]() - Visit Would you like me to provide a general answer based on broader voice AI knowledge instead

?

​ To learn more, see the sources I considered: [[1] Troubleshooting AI Voice Agent Issues | Retell AI](https://www.retellai.com/blog/troubleshooting-common-issues-in-voice-agent-development) [[2] Update Voice Agent](https://docs.retellai.com/api-references/update-agent) [[3] Get Voice Agent](https://docs.retellai.com/api-references/get-agent) [[4] Create Voice Agent](https://docs.retellai.com/api-references/create-agent) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

@AI Evy this is happening on more agents I built 8 months ago. Why is your software failing without notifying me? I can’t fix it

### Answer I understand this is frustrating, especially with multiple live agents affected. Based on the platform changelog, there have been several model deprecations and upgrades that could impact agents built 8 months ago [(1) ]() : Recent Model Deprecations: - OpenAI: gpt-4o → gpt-4.1, gpt-4o-mini → gpt-4.1-mini - Anthropic: claude-3.7-sonnet and claude-4.0-sonnet → claude-4.5-sonnet - Google: gemini-2.0-flash → gemini-2.5-flash, gemini-2.0-flash-lite → gemini-2.5-flash-lite The changelog notes that "The following LLM models have been deprecated. Please update your agents to the latest models" . If your 8-month-old agents were using these deprecated models, they may have been automatically upgraded or are experiencing compatibility issues. Voice Provider Changes: The platform also introduced Cartesia Voice as a partner, with automatic fallback options if primary providers go down . Additionally, there were improvements to voice fallback systems with "Smart voice fallback" . Immediate Actions: 1. Check which LLM models your affected agents are using 2. Manually update to the current supported models (gpt-4.1, claude-4.5-sonnet, gemini-2.5-flash) 3. Review voice provider settings and consider enabling fallback options For urgent support with multiple live agents failing: - Visit [Documentation]() - Ask questions on [Discord]() - Visit

​ To learn more, see the sources I considered: [[1] Platform Changelogs | Retell AI](https://www.retellai.com/changelog) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.