Error to test send mail with SMTP


I have filled my mail settings into nextcloud configuration by using the accound on Microsoft 365 (with, when i hit the button « send test mail ». It shows an error that it can’t send the mail

I have set the “mail_smtpdebug” => true; into file configuration of nextcloud but i can’t find the log file ?

Thanks by advance

Nextcloud version (eg, 20.0.5): Nextcloud Hub 6 (27.1.1)
Operating system and version (eg, Ubuntu 20.04): docker image on QNAP
Apache or nginx version (eg, Apache 2.4.25): nginx
PHP version (eg, 7.4): 8.2.10

Had the same problem:
After digging found in link

so I set:
“log_type” => “file”,
“logfile” => “nextcloud.log”,
and found login in the GUI