Email not sent using sendmail provider

System Information
  • Strapi Version: 4.2.0
  • Operating System: Ubuntu 20.04.4 LTS
  • Database: sqlite
  • Node Version: 16.15.1
  • NPM Version: 8.11.0
  • Yarn Version:

Hi there
I have a Strapi instance configured to use sendmail as email provider. sendmail seems to be configured correctly in the host machine as doing sendmail -v <recipient@email.address> correctly sends the email.

So, I’ve configured Strapi to use sendmail following the documentation using the admin Email plugin configuration but when testing sending an email, absolutely nothing happens (no apparent errors, no email sent).

Does anyone know how to debug issues like this? (I’ve tried DEBUG in command line -leveraging the debug npm package- but no useful traces.)
May anyone point me a more detailed configuration than that one in the docs, in the case I’ve missed something small but important?

Thanks!!

ps: no traces in the system logs for the email (located in /var/log/email.log)