# Call disconnection reasons Please note that when phone numbers enagage in a lot of short calls in a short period, it might be marked as spam at carrier level, which in turn leads to number being blocked and show up as dial\_failed. | Disconnection Reason | Description | | --------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- | | user\_hangup | Expected behavior, user hangup the call. | | agent\_hangup | Expected behavior, AI agent hangup the call. | | call\_transfer | Expected behavior, AI agent transferred the call. | | voicemail\_reached | Expected behavior, if AI agent configured voicemail settings, and reached voicemail. | | inactivity | Expected behavior, call was terminated due to the “end\_call\_after\_silence\_ms” setting reached after long inactivity. | | machine\_detected | Expected behavior, call was terminated due to the “drop\_call\_if\_machine\_detected” setting triggering when an voicemail or similar is detected. | | max\_duration\_reached | Expected behavior, call was terminated due to maximum duration reached. | | concurrency\_limit\_reached | Error, concurrency limit reached, add a retry with exponential backoff. Or consider enterprise plan. | | no\_valid\_payment | Error, no valid payment registered on file, or service shut down due to bill overdue. | | scam\_detected | Error, scam detected for that particular agent. | | error\_inbound\_webhook | Error, failed to retrieve dynamic variables for inbound phone call. | | dial\_busy | The number dialed in busy. | | dial\_failed | Dailing failed, might be due to callee number is non existent, or the agent number is marked as spam and got blocked. | | dial\_no\_answer | The number dialed did not answer. | | error\_twilio | Error, Twilio websocket connection between TalkStack server encountered an error. | | error\_asr | Error, ASR encountered a problem. | | error\_unspecified | Error, unspecified problem. | | error\_vonage | Error, Vonage websocket connection between TalkStack server encountered an error. | | registered\_call\_timeout | Error, phone call is 30s or more apart from registering. | | | | | | | **You have ran out of credit, and have not added payment account.** To check your credit balance, go to the Dashboard and click on the “Billing” tab. You have been rate limited. Check Concurrency Guide for more info. Apart from these common causes, there are other possible causes for this issue for different scenarios. ​ **Phone Call with Custom Twilio** There’re a couple possible causes for this issue: Check if your Twilio account has enough balance to make the call. Check if your voice webhook for Twilio is correctly set up. You can add logging to see if that’s being called. Check if in voice webhook you returned the correct audio websocket url. Check if your Register Call API is correctly called and returned the correct response. ​ ​ Problem During the call This refers to the broad category of issues that occur during the call, such as: call dropped during the call agent not responding function calling not working --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.talkstack.ai/call/get-call-analysis/call-disconnection-reasons.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.