SMTP Authentication problem

FULL ERROR LOG:

Versions:
WordPress: 5.8.1
WordPress MS: No
PHP: 7.4.23
WP Mail SMTP: 3.0.3

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 1.1.1 11 Sep 2018

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

SMTP Debug:
2021-09-28 11:23:47 Connection: opening to smtp.office365.com:587, timeout=300, options=array()

2021-09-28 11:23:47 Connection: opened

2021-09-28 11 :23:48 SERVER -> CLIENT: 220 AM0PR02CA0183.outlook.office365.com Microsoft ESMTP MAIL Service ready at Tue, 28 Sep 2021 11:23:47 +0000

2021-09-28 11:23:48 CLIENT -> SERVER: EHLO synth-asia.kimihost.de

2021-09-28 11:23:48 SERVER -> CLIENT: 250-AM0PR02CA0183.outlook.office365.com Hello [178.77.76.92]250-SIZE 157286400250-PIPELINING250-DSN250-ENHANCEDSTATUSCODES250-STARTTLS250 -8BITMIME250-BINARYMIME250-CHUNKING250 SMTPUTF8

2021-09-28 11:23:48 CLIENT -> SERVER: STARTTLS

2021-09-28 11:23:48 SERVER -> CLIENT: 220 2.0.0 SMTP server ready

2021-09-28 11:23:48 CLIENT -> SERVER: EHLO synth-asia.kimihost.de

2021-09-28 11:23:48 SERVER -> CLIENT: 250-AM0PR02CA0183.outlook.office365.com Hello [178.77.76.92]250-SIZE 157286400250-PIPELINING250-DSN250-ENHANCEDSTATUSCODES250-AUTH LOGIN XOAUTH2250-8BITMIME250-BINARYMIME250-CHUNKING250 SMTPUTF8

2021-09-28 11:23:48 CLIENT -> SERVER: AUTH LOGIN

2021-09-28 11:23:48 SERVER -> CLIENT: 334 VXNlcm5hbWU6

2021-09-28 11:23:48 CLIENT -> SERVER: [credentials hidden]

2021-09-28 11:23:48 SERVER -> CLIENT: 334 UGFzc3dvcmQ6

2021-09-28 11:23:48 CLIENT -> SERVER: [credentials hidden]

2021-09-28 11:23:54 SERVER -> CLIENT: 535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Tenant. Visit https://aka.ms/smtp_auth_disabled for more information. [AM0PR02CA0183.eurprd02.prod.outlook.com]

2021-09-28 11:23:54 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. [AM0PR02CA0183.eurprd02. prod.outlook.com]

SMTP Error: Could not authenticate.

2021-09-28 11:23:54 CLIENT -> SERVER: QUIT

2021-09-28 11:23:54 SERVER -> CLIENT: 221 2.0.0 Service closing transmission channel

2021-09-28 11:23:54 Connection: closed

SMTP Error: Could not authenticate.

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