Problem with SMTP authentication

[intheboat]

Script URL: internal
Version of script: 3.4.3
Hosting company: selfhosted
URL of phpinfo.php:
URL of session_test.php:
What terms did you try when SEARCHING for a solution:
SMTP ANONYMOUS AUTHENTICATION

I'm trying to setup SMTP email however getting the error response from the server below. Our server does not use any username/password for authentication. Is there any way to fix this?

2023-11-01 14:24:21 SERVER -> CLIENT: 220 USODPWPMB001.XXXXXXXXX.int Microsoft ESMTP MAIL Service ready at Wed, 1 Nov 2023 07:24:21 -0700
2023-11-01 14:24:21 CLIENT -> SERVER: EHLO wmsppwvwb006
2023-11-01 14:24:22 SERVER -> CLIENT: 250-USODPWPMB001.XXXXXXXXX.int Hello [10.188.96.56]
250-SIZE 52428800
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-STARTTLS
250-X-ANONYMOUSTLS
250-AUTH GSSAPI NTLM
250-X-EXPS GSSAPI NTLM
250-8BITMIME
250-BINARYMIME
250-CHUNKING
250 XRDST

[Klemen]

What is the error message in the red error box that appears (above the log message you posted)?