# Sending Mail via Microsoft 365 Channel fails with 451 4.7.0 Temporary server error. Please try again later. PRX4

**URL:** https://community.zammad.org/t/sending-mail-via-microsoft-365-channel-fails-with-451-4-7-0-temporary-server-error-please-try-again-later-prx4/5996
**Category:** Technical assistance
**Created:** [January 8, 2021, 12:35am UTC](https://community.zammad.org/t/sending-mail-via-microsoft-365-channel-fails-with-451-4-7-0-temporary-server-error-please-try-again-later-prx4/5996 "2021-01-08T00:35:20Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![grafjo](https://community.zammad.org/user_avatar/community.zammad.org/grafjo/32/3685_2.png) [@grafjo](https://community.zammad.org/u/grafjo)
#### Post date: [January 8, 2021, 12:35am UTC](https://community.zammad.org/t/sending-mail-via-microsoft-365-channel-fails-with-451-4-7-0-temporary-server-error-please-try-again-later-prx4/5996/1 "2021-01-08T00:35:20Z")

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### Infos:

- Used Zammad version: 3.6.x
- Used Zammad installation source: helm-chart
- Small setup without running elasticsearch
- Browser + version: Chrome 87
- Microsoft 365 / Office 365 User Account with MFA

### Expected behavior:

- Adding an account to Microsoft 365 channel and receiving / sending mails is working

### Actual behavior:

- Adding the account to Microsoft 365 channel works
- Receiving mail works, too
- Sending mails via this channel fails with

> Can’t use Channel::Driver::Smtp: #\<Net::SMTPAuthenticationError: 451 4.7.0 Temporary server error. Please try again later. PRX4 [[FR2P281CA0025.DEUP281.PROD.OUTLOOK.COM](http://FR2P281CA0025.DEUP281.PROD.OUTLOOK.COM)] \>

- The Scheduler reschedules this mail delivery but still failing

### Steps to reproduce the behavior:

- Setup Microsoft 365 channel via [Microsoft 365 IMAP Email — Zammad Admin Documentation documentation](https://admin-docs.zammad.org/en/latest/channels/microsoft365/index.html)

Maybe one of you have an idea how I can solve this issue? Thx.

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<div class="post-metadata">

### Author: ![grafjo](https://community.zammad.org/user_avatar/community.zammad.org/grafjo/32/3685_2.png) [@grafjo](https://community.zammad.org/u/grafjo)
#### Post date: [January 12, 2021, 9:22pm UTC](https://community.zammad.org/t/sending-mail-via-microsoft-365-channel-fails-with-451-4-7-0-temporary-server-error-please-try-again-later-prx4/5996/2 "2021-01-12T21:22:32Z")

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Ok I found a solution:

- Make sure authenticated client SMTP submission is enabled - Details here [Enable or disable SMTP AUTH | Microsoft Docs](https://docs.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/authenticated-client-smtp-submission)
- Disable MFA for that mailbox

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### Author: ![system](https://community.zammad.org/uploads/default/original/1X/5c5afaea2d23f811dbec33cd4edb02fa29d3262f.png) [@system](https://community.zammad.org/u/system)
#### Post date: [May 12, 2021, 9:22pm UTC](https://community.zammad.org/t/sending-mail-via-microsoft-365-channel-fails-with-451-4-7-0-temporary-server-error-please-try-again-later-prx4/5996/3 "2021-05-12T21:22:35Z")

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