This browser is no longer supported.
Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(128, 8%, 22%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EA%3C/text%3E%3C/svg%3E)
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.
Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.
This answer has been deleted due to a violation of our Code of Conduct. The answer was manually reported or identified through automated detection before action was taken. Please refer to our Code of Conduct for more information.
Comments have been turned off. Learn more
If you are using desktop Outlook and are on versions 2010 or 2013, openid authentication (on top of Oauth2) is not supported by 2010 and is only supported via a registry change in 2013.
Thanks timme,
It worked! Great job!
Almost scratch my head when i configured xerox printer to relay scanned pdf through office 365.
Never had a problem with other tenant before, now i'm having this kind of problem.
Thanks microsoft managed service, great job.
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
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?