Good evening,
Is it possible to use a Zimbra mail account to send emails automatically (e.g., notifications, password resets, newsletters, etc.)?
Kind regards, Henri Sardeaul
Yes, it's perfectly possible to use a Zimbra mail account to send all kinds of automated emails.
The most common way for application notifications or password resets is to configure your application to use OVHcloud's SMTP servers.
The key here is to set up sending through port 587 (or 465 with SSL). Mail servers communicate with each other on port 25, but for your application to send emails via OVH's server, you should use the client‑mail submission port, which is 587 (with STARTTLS) or 465 (with SSL).
You’ll find the SMTP configuration details in your client area, under the section for your mail account.
I hope I’ve helped you,
Sergio Turpín
To make sure the automatic emails you send with your Zimbra account land in the inbox and not in the spam folder, it’s highly recommended that you correctly configure your domain’s authentication records in the DNS zone. This includes SPF, DKIM, and DMARC.
Take a look at this link:
These records increase the trust of mail servers (like Gmail or Outlook) and dramatically improve the deliverability of your emails.
If you have any questions about the setup, let us know 
Sergio Turpín
Transactional emails, yes, but absolutely not newsletters (forbidden).
Ok, anyway I wasn't going to use it for this, it was just to learn about transactional emails