---
title: "Receiving a Busy Signal/Call Drop when an Auto Attendant Forwards out to an External Line"
slug: "receiving-a-busy-signal-call-drop-when-an-auto-attendant-forwards-out"
updated: 2026-06-30T07:18:46Z
published: 2026-06-30T07:18:46Z
canonical: "help.8x8.com/receiving-a-busy-signal-call-drop-when-an-auto-attendant-forwards-out"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://help.8x8.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Receiving a Busy Signal/Call Drop when an Auto Attendant Forwards out to an External Line

### Symptom

When using an Auto Attendant to dial out to an external line, you receive a busy signal/call drop.

### Applies to

- Admin Console
- Auto Attendants

### **Resolution**

For an Auto Attendant to forward calls out to an external number, the phone number receiving the inbound call must be assigned to a user or service first. **An unassigned number will not support forwarding to an off‑net (external) destination.** You need to involve a user/number in some way:

- One method would be to assign a number to the Auto Attendant.
- The second method is to assign the Auto Attendant’s 8x8 number to a user account, then configure that user’s call forwarding to the external number. Calls to the AA number are then forwarded out via that user’s forwarding rules.
- Another method is to forward calls from the Auto Attendant to a user or ring group, and then configure that user/ring groups call forwarding rules to dial out to the external number.

The above approaches rely on a number being associated with either the Auto Attendant, with a user or extension that handles the external forwarding.

> [!NOTE]
> Note:
> 
> Essentially, when placing a call to the Auto Attendant to forward out to the external line from the Auto Attendant that is not assigned to a number, there is no phone number to associate with the call, and the carrier rejects it with a **403 FORBIDDEN**.

### Causes

- Concurrent external calls has been reached
- No user/service/number is assigned to the Auto Attendant