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voicemail detection issues
# support
m
its not detecting voicemails instead it shows the log as customer did not answer, my voicemail detection is sat to vapi and default settings. is there anything I can do to make it show voicemail instead?
c
Hi there, Thank you for your message. Our team is currently out of the office. We operate Monday through Friday, from 9:00 AM to 8:00 PM Pacific Standard Time (PST). We’ll get back to you as soon as possible during our normal business hours. If your message is urgent, please mark it accordingly or include “URGENT” in the subject line, and we’ll do our best to respond promptly. Warm regards, Vapi Customer Support Team
v
To improve voicemail detection with the Vapi provider, try making detection more aggressive by lowering the 
startAtSeconds
and increasing 
maxRetries
. Update your assistant configuration as follows:
Copy code
json
"voicemailDetection": {
  "provider": "vapi",
  "backoffPlan": {
    "startAtSeconds": 1.5,
    "frequencySeconds": 2.5,
    "maxRetries": 8
  }
}
Test this change to see if voicemails are detected more reliably in your logs. Source: Vapi documentation on missed voicemail troubleshooting.
m
it still shows customer-did-not-answer rather than "voicemail"...
@Vapi Support Bot it still shows customer-did-not-answer rather than "voicemail"...
Urgent
v
To improve voicemail detection and help ensure calls are logged as "voicemail" instead of "customer-did-not-answer," try increasing the 
beepMaxAwaitSeconds
parameter to allow more time for the voicemail beep. Update your configuration as follows:
Copy code
json
"voicemailDetection": {
  "provider": "vapi",
  "backoffPlan": {
    "startAtSeconds": 1.5,
    "frequencySeconds": 2.5,
    "maxRetries": 8
  },
  "beepMaxAwaitSeconds": 25
}
Test this setting—most voicemail systems need 20-30 seconds before the beep. If the issue persists, further troubleshooting may be required. (Source: Vapi documentation on voicemail detection best practices)
m
where can i find the "beepMaxAwaitSeconds": 25 on Vapi?
Urgent
@Vapi Support Bot
v
To set 
"beepMaxAwaitSeconds"
in Vapi, add or update it in your assistant's configuration JSON under the 
voicemailDetection
section. For example:
Copy code
json
"voicemailDetection": {
  "provider": "vapi",
  "backoffPlan": {
    "startAtSeconds": 1.5,
    "frequencySeconds": 2.5,
    "maxRetries": 8
  },
  "beepMaxAwaitSeconds": 25
}
You can update this setting via the API or in your assistant's configuration file. There is no mention in the documentation of a specific UI toggle for this parameter—it's set in the config JSON. (Source: Vapi documentation on voicemail detection configuration)
m
i tried those updated values it still shows Customer Did Not Answer rather than voicemail
@Vapi Support Bot
Urgent
v
Thank you for confirming you've updated the 
voicemailDetection
settings as recommended. To help diagnose further, could you let me know which telephony provider or carrier's voicemail system you are calling (e.g., mobile carrier, VoIP, etc.)? Some systems may require different detection strategies. This info will help determine if a provider switch (e.g., to Google or OpenAI) or further configuration is needed. Source: - [Vapi Voicemail Detection Documentation](https://docs.vapi.ai/calls/voicemail-detection)
m
I am using twilio
@Vapi Support Bot
v
Since the Vapi provider settings did not resolve voicemail detection with Twilio, try switching to the Google provider for improved accuracy. Update your assistant configuration as follows:
Copy code
json
"voicemailDetection": {
  "provider": "google",
  "backoffPlan": {
    "startAtSeconds": 3,
    "frequencySeconds": 3,
    "maxRetries": 8
  },
  "beepMaxAwaitSeconds": 20
}
Apply this change and test again—Google's provider is recommended for maximum accuracy with some voicemail systems. (Source: Vapi documentation on provider-specific voicemail detection)
m
I tried those updated values and it still shows "Customer did not answer"
@Vapi Support Bot
v
Thank you for your patience. Since updating both the provider and configuration hasn't resolved the issue, could you please confirm which detection type you are currently using in your 
voicemailDetection
settings (e.g., 
"type": "audio"
or 
"type": "transcript"
)? This detail will help determine the next best troubleshooting step. If possible, please share a snippet of your current 
voicemailDetection
configuration (with sensitive info removed). Source: - [Vapi Voicemail Detection Documentation](https://docs.vapi.ai/calls/voicemail-detection)
m
ok i just tested it on a different vapi account with this configuration
Copy code
json
{

  "model": {
    "model": "gpt-4.1-mini",
    "toolIds": ["tool-id-redacted"],
    "messages": [
      {
        "role": "system",
        "content": "[System prompt text kept intact — but all client names, phone numbers, and sensitive details have been anonymized.]"
      }
    ],
    "provider": "openai",
    "temperature": 0.3
  },
  "firstMessage": "Hi {{first_name}}?",

  "voicemailDetection": {
    "provider": "vapi",
    "backoffPlan": {
      "maxRetries": 6,
      "startAtSeconds": 5,
      "frequencySeconds": 5
    },
    "beepMaxAwaitSeconds": 0
could it be the open ai model thats being used?
@Vapi Support Bot
on the configuraiton above it did detect its a voicemail and worked fine, but on the other account it still shows customer did not answer
v
Thank you for sharing your configuration. To help pinpoint the issue, could you please confirm what value you are using for the 
"type"
field in your 
voicemailDetection
settings (e.g., 
"audio"
or 
"transcript"
)? Tip: For best results with the OpenAI provider, 
"type": "transcript"
is recommended. For Vapi or Google, 
"type": "audio"
is usually optimal. (Reference: [Vapi Voicemail Detection Documentation](https://docs.vapi.ai/calls/voicemail-detection)) Source: - [Vapi Voicemail Detection Documentation](https://docs.vapi.ai/calls/voicemail-detection)
d
@Mahmood I thought I was going crazy myself too. Friday shortly after starting the outbound calls, 100% of my calls were 0 seconds customer did not answer only. I also use Twilio.
m
I fixed it
It was an easy fix
But it took so much time for me to figure it out
d
@Mahmood what ended up being the fix for you?
v
Message marked as helpful by @GIDEON! 🎉
j
@Mahmood Same, can you share how you solved?
m
set a voice mail message 😂 that's been the fix @julian @Dr House
you have to actually write down a voice mail message
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