Do you have any direction as to: 1. make sure we reduce these dropped calls? 2. workarounds repeated dropping calls to one number?

Thank you for sharing the issue. To help pinpoint the cause of the dropped calls, could you let me know if you see any specific error messages or "endedReason" codes in your call logs for the affected calls?

Hi undergrowthseer, To troubleshoot the issue where a call drops immediately after initiating a transfer, follow these steps: 1. **Check Call Ended Reason**: Use the API to get the call details and verify the

endedReason

. If it's not

"assistant-forwarded-call"

, review your assistant configuration to ensure the transfer was initiated correctly. 2. **Server Message Configuration**: - Ensure your assistant’s

serverMessages

configuration doesn't override Vapi’s call control by including

"phone-call-control"

, unless using custom transfer logic. 3. **Phone Call Provider Bypass**: - Set

phoneCallProviderBypassEnabled

to

false

for standard Vapi forwarding, unless using custom provider call control. 4. **Validate Transfer Scenario Compatibility**: Make sure your transfer scenarios are supported. For example, web-to-phone transfers are not supported. 5. **Analyze Telephony Provider Logs**: - Use the

phoneCallProviderId

from the call object to check provider logs for any transfer-related errors. For SIP-based calls, you may also need to analyze the SIP packets for any issues regarding the transfer requests. For more detailed instructions, you can refer to the [Debug Call Forwarding Drops](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops) guide.

thanks i will check this out. this issue we're having is a direct call to a phone number (using twilio) and also the same but more frequent with whatsapp calls. willl this be the same troubleshooting process for whatsapp calls? what i do with whatsapp is that i put a request in and use the streaming link to pass back to twilio. is that accurate? do i still need to set

phoneCallProviderBypassEnabled

to false?

Hi undergrowthseer, If you're experiencing issues with calls dropping immediately after initiating a transfer, here's a concise troubleshooting guide you may try: 1. Check Call Ended Reason - Use the following cURL command to get the call details:

sh
     $ curl -X GET "https://api.vapi.ai/call/{call_id}" \
       -H "Authorization: Bearer YOUR_API_KEY" \
       -H "Content-Type: application/json"

- Verify if the

endedReason

is

"assistant-forwarded-call"

. If not, review your assistant configuration. 2. Verify Server Message Configuration - Ensure your assistant’s serverMessages does not contain

"phone-call-control"

, as this overrides Vapi’s transfer logic. 3. Check Phone Call Provider Bypass - Ensure

phoneCallProviderBypassEnabled

is set to

false

unless you are handling calls through a custom provider. 4. Validate Transfer Scenario Compatibility - Confirm your transfer scenario is supported (e.g., Phone call to Phone number is supported, Web call to Phone number is not). 5. Analyze Telephony Provider Logs - If Vapi's log shows successful forwarding, check your telephony provider's logs using

phoneCallProviderId

for any transfer errors. 6. SIP Packet Analysis (for SIP calls) - Download and review the PCAP file for SIP transfers using Wireshark: - Look for

REFER

packets to see if a transfer request was sent. - Check for error responses which indicate rejection by the SIP provider. For more information, you can refer to the [Debug call forwarding drops](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops) documentation. This should help in identifying the root cause of the dropped calls during forwarding. Let me know if you need further assistance.

how did you set phoneCallProviderBypassEnabled to false @undergrowthseer

The

phoneCallProviderBypassEnabled

flag is a configuration setting that determines whether Vapi handles call control directly. Here's the recommended configuration[1](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops):

{
  "phoneCallProviderBypassEnabled": false
}

For call forwarding to work properly through Vapi, this setting should be

false

. Setting this to

true

should only be done if you're implementing custom call control through your telephony provider.