---
title: "Contact Center SMTP Configuration for Office 365"
slug: "contact-center-smtp-configuration-for-office-365"
updated: 2026-05-11T09:20:16Z
published: 2026-05-21T21:25:40Z
canonical: "help.8x8.com/contact-center-smtp-configuration-for-office-365"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://help.8x8.com/llms.txt
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# Contact Center SMTP Configuration for Office 365

## Symptom

When setting up a Custom SMTP with Office 365 in the 8x8 Contact Centre, the test in the Configuration Manager succeeds; however, outbound emails fail to send and are not received by the recipients.

## Applies To

- 8x8 Contact Centre Custom SMTP with Office 365
- Outbound Email from 8x8 Contact Centre

## Resolution

The test from Configuration Manager can sometimes provide a successful result even though the SMTP connection from 8x8 Contact Centre fails. This is often due to an unsupported Authentication Method being selected. Only the "Password, transmitted insecurely (LOGIN)" authentication method is supported for Office 365 accounts.

### Example Office 365 Custom SMTP Configuration

Server Name: smtp.office365.com

Port: 587

Connection Security: STARTTLS

Authentication Method: Password, transmitted insecurely (LOGIN)

## Cause

This is often due to an unsupported Authentication Method being selected.

## Additional Information

[Set up a Custom SMTP Server for 8x8 Contact Center Email Communication](/support/docs/set-up-a-custom-smtp-server-for-8x8-contact-center-email-communication)

[8x8 Contact Center Manuals & User Guides](/support/docs/8x8-contact-center-manuals-user-guides)