Set up a Zimbra account on Outlook for Android app

Source:
https://support.microsoft.com/en-gb/office/set-up-email-in-the-outlook-for-android-app-886db551-8dfa-4fd5-b835-f8e532091872#tab=bkmk_manual

In Outlook for Android, go to Settings Settings > Add Account > Add Email Account.

Enter email address. Tap Continue.

Tap Setup account manually if available, and then on the email provider page choose Exchange and toggle Advanced Settings on.

Enter your server setting details, if available and then tap the checkmark icon.

Server settings:
Server host name: zmail2.his.com

Incoming Server Settings

Domain\Username
Enter your full email address, such as yourname@yourdomain.com.

Password
Use the password that you use to access your email.

Server

Exchange accounts
use:   zmail2.his.com

Port
Use 993.

Security type
Select SSL/TLS or make sure the Use secure connection (SSL) checkbox is checked, then tap Next.

Outgoing SMTP Server Settings

SMTP Server

    Exchange accounts
    use:   zmail2.his.com

Security Type
Choose TLS.

Port Number
Enter 587. Tap Next.

You may be prompted to enter your email account password again or agree to/activate any necessary permissions.