---
title: "Poly VVX 300 and VVX 400 Phones Unable to Connect to Network"
slug: "poly-vvx-300-and-vvx-400-phones-unable-to-connect-to-network"
updated: 2026-05-22T12:02:42Z
published: 2026-05-22T12:02:42Z
canonical: "help.8x8.com/poly-vvx-300-and-vvx-400-phones-unable-to-connect-to-network"
stale: true
---

> ## 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.

# Poly VVX 300 and VVX 400 Phones Unable to Connect to Network

## Symptom

When connecting Poly VVX 300 and VVX 400 phones to a gigabit network, the phone does not connect. The phones may display Line Unregistered, and the time and date are out of sync.

## Applies To

- Poly VVX 300 and VVX 400

## Resolution

### Set LAN Speed to 100FD in Phone Admin Menu

To change both LAN port and PC port speeds to 100 FD (full duplex)L

1. On the phone, go to **Menu** > **Settings**. ![Settings-300x150.jpg](https://cdn.us.document360.io/e3a59e39-abd3-4423-964c-0a4008dc5673/Images/Documentation/10263)
2. Select **Advanced**. ![Advanced-300x150.jpg](https://cdn.us.document360.io/e3a59e39-abd3-4423-964c-0a4008dc5673/Images/Documentation/10262)
3. Enter [password](/business-phone/voice/admin-console/setup/devices/device-administrator-password/). ![Password-300x150.jpg](https://cdn.us.document360.io/e3a59e39-abd3-4423-964c-0a4008dc5673/Images/Documentation/10261)
4. Select **Administration Settings**. ![Admin-300x150.jpg](https://cdn.us.document360.io/e3a59e39-abd3-4423-964c-0a4008dc5673/Images/Documentation/10264)
5. Select **Network Configuration** > **Ethernet Menu**. ![](https://cdn.us.document360.io/e3a59e39-abd3-4423-964c-0a4008dc5673/Images/Documentation/11832)
6. Scroll down and select **LAN Port Mode**. ![](https://cdn.us.document360.io/e3a59e39-abd3-4423-964c-0a4008dc5673/Images/Documentation/11830)
7. For the **Speed Setting**, select **100FD** (100 mbps Full Duplex). ![](https://cdn.us.document360.io/e3a59e39-abd3-4423-964c-0a4008dc5673/Images/Documentation/11831)
8. Go back to the **Ethernet Menu** and select **PC Port Mode**.
9. For the **Speed Setting**, select **100FD**.
10. Return to the main menu. You will be prompted to **Save** the configuration and reboot the phone.

## Cause

Poly VVX 300 and VVX 400 phones are not rated to gigabit speed, so they cannot use that connection speed. These phones are designed to auto-negotiate, but this does not always happen.

> [!NOTE]
> Note:
> 
> If the phone gets a DHCP IP address, this is a separate issue.