Using the Mailer “Other SMTP” to connect to Office365 account

Here is the error log:

Versions:
WordPress: 6.1.1
WordPress MS: No
PHP: 7.4.33
WP Mail SMTP: 3.7.0

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 1.1.1p 21 Jun 2022
Apache.mod_security: No

Debug:
Email Source: WP Mail SMTP
Mailer: Other SMTP
SMTP Error: Could not authenticate.

SMTP Debug:
2023-01-23 04:48:39 Connection: opening to smtp.office365.com:587, timeout=300, options=array()

2023-01-23 04:48:39 Connection: opened

2023-01-23 04:48:39 SERVER -> CLIENT: 220 SYCP282CA0024.outlook.office365.com Microsoft ESMTP MAIL Service ready at Mon, 23 Jan 2023 04:48:38 +0000

2023-01-23 04:48:39 CLIENT -> SERVER: EHLO developabilities.au

2023-01-23 04:48:39 SERVER -> CLIENT: 250-SYCP282CA0024.outlook.office365.com Hello [2400:b800:3:1::6b]250-SIZE 157286400250-PIPELINING250-DSN250-ENHANCEDSTATUSCODES250-STARTTLS250-8BITMIME250-BINARYMIME250-CHUNKING250 SMTPUTF8

2023-01-23 04:48:39 CLIENT -> SERVER: STARTTLS

2023-01-23 04:48:39 SERVER -> CLIENT: 220 2.0.0 SMTP server ready

2023-01-23 04:48:39 CLIENT -> SERVER: EHLO developabilities.au

2023-01-23 04:48:39 SERVER -> CLIENT: 250-SYCP282CA0024.outlook.office365.com Hello [2400:b800:3:1::6b]250-SIZE 157286400250-PIPELINING250-DSN250-ENHANCEDSTATUSCODES250-AUTH LOGIN XOAUTH2250-8BITMIME250-BINARYMIME250-CHUNKING250 SMTPUTF8

2023-01-23 04:48:39 CLIENT -> SERVER: AUTH LOGIN

2023-01-23 04:48:39 SERVER -> CLIENT: 334 VXNlcm5hbWU6

2023-01-23 04:48:39 CLIENT -> SERVER: [credentials hidden]

2023-01-23 04:48:39 SERVER -> CLIENT: 334 UGFzc3dvcmQ6

2023-01-23 04:48:39 CLIENT -> SERVER: [credentials hidden]

2023-01-23 04:48:44 SERVER -> CLIENT: 535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Tenant. Visit https://aka.ms/smtp_auth_disabled for more information. [SYCP282CA0024.AUSP282.PROD.OUTLOOK.COM]

2023-01-23 04:48:44 SMTP ERROR: Password command failed: 535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Tenant. Visit https://aka.ms/smtp_auth_disabled for more information. [SYCP282CA0024.AUSP282.PROD.OUTLOOK.COM]

SMTP Error: Could not authenticate.

2023-01-23 04:48:44 CLIENT -> SERVER: QUIT

2023-01-23 04:48:44 SERVER -> CLIENT: 221 2.0.0 Service closing transmission channel

2023-01-23 04:48:44 Connection: closed

SMTP Error: Could not authenticate.

Hi @mavtect

Thanks for reaching out to us and we’re sorry to hear that you’re experiencing issues with the Other SMTP mailer.

1. The Pro version of WP Mail SMTP is only necessary in your case if you’re already using paid email services with Microsoft, as you’ll have the benefit of high email sending limits without signing up for a separate service. As a workaround, you can still connect using SMTP credentials by following the instructions outlined in our Other SMTP documentation.
2. Yes, an APP password is required as mentioned in this section of our documentation where we provide instructions for generating an app password for several different services. Please search for the heading that says “Generating an App Password in Outlook“.

The error log confirms that the main issue is that you were unable to authenticate using the credentials that were inserted.

I hope this helps ??