Office 365 SMTP authentication failing, even with correct account information

Anonymous

On my Wordpress site I've run into a problem in the last day or so, where emails simply fail to send. Before today it was running flawlessly for two months. The account information/password/username etc have not changed in that two months.

I'm using a Wordpress plugin called WP Mail SMTP to facilitate the sending of all outgoing emails. The error log I'm getting from the email test on that is as follows:

Versions:

WordPress: 5.3.2

WordPress MS: No

PHP: 7.3.14-5+0~20200202.52+debian9~1.gbpa71879

WP Mail SMTP: 1.8.1

Params:

Mailer: smtp

Constants: No

ErrorInfo: SMTP Error: Could not authenticate.

Host: smtp.office365.com

Port: 587

SMTPSecure: tls

SMTPAutoTLS: bool(true)

SMTPAuth: bool(true)

Server:

OpenSSL: OpenSSL 1.1.1d 10 Sep 2019

SMTP Debug:

2020-02-10 16:36:56 Connection: opening to smtp.office365.com:587, timeout=300, options=array ()

2020-02-10 16:36:56 Connection: opened

2020-02-10 16:36:56 SERVER -> CLIENT: 220 LNXP123CA0008.outlook.office365.com Microsoft ESMTP MAIL Service ready at Mon, 10 Feb 2020 16:36:55 +0000

2020-02-10 16:36:56 CLIENT -> SERVER: EHLO www.*****.com

2020-02-10 16:36:56 SERVER -> CLIENT: 250-LNXP123CA0008.outlook.office365.com Hello [***]250-SIZE 157286400250-PIPELINING250-DSN250-ENHANCEDSTATUSCODES250-STARTTLS250-8BITMIME250-BINARYMIME250-CHUNKING250 SMTPUTF8

2020-02-10 16:36:56 CLIENT -> SERVER: STARTTLS

2020-02-10 16:36:56 SERVER -> CLIENT: 220 2.0.0 SMTP server ready

2020-02-10 16:36:56 CLIENT -> SERVER: EHLO www.zestpromotional.com

2020-02-10 16:36:56 SERVER -> CLIENT: 250-LNXP123CA0008.outlook.office365.com Hello [***]250-SIZE 157286400250-PIPELINING250-DSN250-ENHANCEDSTATUSCODES250-AUTH LOGIN XOAUTH2250-8BITMIME250-BINARYMIME250-CHUNKING250 SMTPUTF8

2020-02-10 16:36:56 CLIENT -> SERVER: AUTH LOGIN

2020-02-10 16:36:56 SERVER -> CLIENT: 334 VXNlcm5hbWU6

2020-02-10 16:36:56 CLIENT -> SERVER: c2FsZXNAemVzdHByb21vdGlvbmFsLmNvbQ==

2020-02-10 16:36:56 SERVER -> CLIENT: 334 UGFzc3dvcmQ6

2020-02-10 16:36:56 CLIENT -> SERVER: QmFkMzM4MzA=

2020-02-10 16:37:02 SERVER -> CLIENT: 535 5.7.3 Authentication unsuccessful [LNXP123CA0008.GBRP123.PROD.OUTLOOK.COM]

2020-02-10 16:37:02 SMTP ERROR: Password command failed: 535 5.7.3 Authentication unsuccessful [LNXP123CA0008.GBRP123.PROD.OUTLOOK.COM]

SMTP Error: Could not authenticate.

2020-02-10 16:37:02 CLIENT -> SERVER: QUIT

2020-02-10 16:37:02 SERVER -> CLIENT: 221 2.0.0 Service closing transmission channel

2020-02-10 16:37:02 Connection: closed

SMTP Error: Could not authenticate.

Does anyone have any ideas at all? I'm completely at a loss here.

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48 answers

Anonymous

I don't believe that i post solution thatch work onmicrosoft.com only accept solution should be slc /scannowYou have to enable Authenticated SMTP then wait 3 minutes.Open the Microsoft 365 admin center and go to Users > Active users.

Select the user, and in the flyout that appears, click Mail.

In the Email apps section, click Manage email apps.

Verify the Authenticated SMTP setting: unchecked = disabled, checked = enabled.

When you're finished, click Save changes.

This solve my problem..

When my admin entered the screen, this option was already checked in my account, so he deselected, saved, closed the screen (I don't know if it is necessary), entered again, selected again and saved.

I waited 5 minutes, and updated the configuration in gmail.

And work

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Anonymous

2020-09-26T21:51:21+00:00
I don't believe that i post solution thatch work onmicrosoft.com only accept solution should be slc /scannowYou have to enable Authenticated SMTP then wait 3 minutes.Open the Microsoft 365 admin center and go to Users > Active users.
```
Select the user, and in the flyout that appears, click Mail.

In the Email apps section, click Manage email apps.

Verify the Authenticated SMTP setting: unchecked = disabled, checked = enabled.

When you're finished, click Save changes.
```
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Anonymous

2020-09-08T22:49:51+00:00

I can't get these powershell permissions to take as I don't have the right role to execute cmdlet Get-TransportConfig. This is super frustrating as the SMTP server fails the authentication of the user every time. Opening a support ticket with MSFT as we've had no email on Wordpress now for four weeks. Ugh.
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Anonymous

2020-08-13T19:39:05+00:00

Thanks.

It is this very setting that leaves me even more confused! I have several email accounts under different tenants and they all have this setting disallowed - and yet email sent via SMTP to MSFT 365 Exchange (with PHPMailer) using Basic Authentication continues to work fine.

Are we to assume that this setting only refers to openid / Oauth2 authentication?
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Anonymous

2020-08-13T16:57:22+00:00

Hey everyone,

For anyone facing the failing authentication issue, I can suggest one thing to try that did solve the problem for me. Granted, there are many possible sources of the problem, so this suggestion won't necessarily fix the issue of course.

In your Microsoft 365 Admin Center under the User tab, you have the ability to allow/disallow Email Apps. Head over to https://admin.microsoft.com/AdminPortal/Home#/users and click on the user that is facing the issues. In the "Email" tab of the modal that opened you'll be able to manage the Email Apps. Select Authenticated SMTP and click save.

In our specific case that fixed the issue.

I hope that helped :)

Cheers
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