---
title: "Error while Syncing Microsoft Exchange Contacts with Active Sync in Work for Desktop"
slug: "error-while-syncing-microsoft-exchange-contacts-active-sync-work-desktop"
updated: 2026-05-17T17:40:01Z
published: 2026-05-21T21:27:46Z
canonical: "help.8x8.com/error-while-syncing-microsoft-exchange-contacts-active-sync-work-desktop"
stale: true
---

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# Error while Syncing Microsoft Exchange Contacts with Active Sync in Work for Desktop

## Symptom

Attempting to sync Microsoft Exchange contacts using Advanced Exchange Active Sync Configuration in 8x8 Work for Desktop results in the following error:

*Can't authenticate with Exchange server. Original Message text follows: [domain of entered Active Sync URL]![Virtual_Office_Desktop_Microsoft_Exchange_Server.png](https://cdn.us.document360.io/e3a59e39-abd3-4423-964c-0a4008dc5673/Images/Documentation/11134)*

## Applies To

- 8x8 Work for Desktop

## Resolution

1. In 8x8 Work for Desktop, navigate to **Settings** > **Contacts**.
2. Select **Company** or **Personal**.
3. At the prompt, enter the primary **Outlook Email** and **Password**.
4. Select the **Advanced Exchange Active Sync Configuration** box.
5. Enter the **Active Sync URL** (use **External URL**).
6. Add the following to the end of the URL entered above: **/EWS/Exchange.asmx**. ***Example****: https://url.example.com/Microsoft-Server-ActiveSync/EWS/Exchange.asmx*
7. Enter the **Login Username** or **Exchange UPN**.
8. Click **OK**.

## Cause

Most likely, one or both of the following hasn't been done:

- Properly enter the **Microsoft-Server-ActiveSync External URL**.
- Add the following to the end of the above URL: **/EWS/Exchange.asmx**.