Overview
When working with Twilio’s Programmable Voice SIP Domains, you may encounter a situation where a SIP Domain name remains unavailable even after deleting the domain and its associated subaccount. This article explains why this happens, what to expect, and how to work around it.
Environment
Twilio Console
What You Need To Know
Summary Table
| Action | Result |
|---|---|
| Delete SIP Domain | Domain enters cooldown (up to 30 days) |
| Delete Subaccount | Domain still in cooldown |
| Create New Subaccount | Domain unavailable until cooldown ends |
| Use Different Domain Name | Immediate availability |
| Wait for Cooldown | Domain becomes available after period |
Below you will find references to useful documents:
Frequently Asked Questions
Why Does This Happen?
SIP Domain Names Must Be Globally Unique:
Twilio requires that every SIP Domain name (e.g., yourdomain.sip.twilio.com) is unique across all Twilio accounts and subaccounts. This prevents conflicts and ensures secure routing.
Deletion Triggers a Cooldown Period:
When you delete a SIP Domain, Twilio places the domain name in a “cooldown” or “quarantine” state. This period typically lasts up to 30 days. The purpose is to prevent immediate reuse, which could cause routing or security issues.
Subaccount Deletion Doesn’t Reset Cooldown:
If you delete a subaccount that contained a SIP Domain, the domain name remains in cooldown. Creating a new subaccount does not make the domain name available again until the cooldown expires.
What Are My Options?
-
Wait for the Cooldown to Expire:
The SIP Domain name will become available again after the cooldown period (usually 30 days from deletion). -
Choose a Different Domain Name:
If you need to proceed immediately, select a new, unique SIP Domain name for your workflow. -
Business-Critical Needs:
If you have an urgent requirement to reuse the exact SIP Domain name before the cooldown expires, reach out to Twilio Support for review. While overrides are not generally available, your request can be evaluated.
Why Is This Policy in Place?
Twilio’s architecture is designed to keep resources and data isolated between accounts and subaccounts. This is especially important for resellers and businesses managing multiple customers. The cooldown period helps maintain security and data integrity, ensuring that deleted domains cannot be immediately claimed by another account.