Understand outbound call disconnection reasons.
When an outbound call is made and a dial_failed
, dial_busy
, dial_no_answer
reason is returned, it means that the outbound call is not successful.
There can be a few reasons for this (we are adding more granular disconnection reasons to improve the visibility into why outbound call dialing fails starting july 1, 2025):
dial_failed
:
dial_busy
:
dial_no_answer
:
Check the call detailed log, it contains the SIP error code and the error message. Most cases this would be enough for you to identify the root cause.
If the call detailed log does not provide enough information, you can try the following:
If using custom telephony
If using numbers purchased from Retell
When a number experience high outbound call volume spike without any warmup, and / or has a low pickup rate, it might be marked as spam by carriers. When this happens, the number will get blocked frequently. To remedy this, you can try to: