Matomo Version: 3.9.1
PHP Version: tested with 7.0.33 and 7.3.3
Middleware: Apache 2.4
OS : Debian

I followed the instructions of https://matomo.org/faq/troubleshooting/faq_115/ to enable log in Matomo.
So I added:

[log]
log_writers[] = file
log_level = DEBUG

in my config/config.ini.php

I checked if the Monolog Plugin was enabled and it was.

But no log file is created.

I try to add

logger_file_path = /var/www/html/tmp/logs/matomo.log

but same result.

I also try to log in database but nothing still visible in LogViewer plugin.

Could you please tell me if I miss something?

Thank you in advance.
Regards,