1. Setup a Nextcloud server by following this video – https://www.youtube.com/watch?v=QXfsi0pwgYw
2. Install the Nextcloud Zimlet and its dependencies on your Zimbra server:
   1. To install on Red Hat and CentOS, run:

      yum install zimbra-zimlet-nextcloud

   2. To install on Ubuntu, run:

      apt-get install zimbra-zimlet-nextcloud

   3. Restart zmmailbox server:

      su - zimbra
      zmmailboxdctl restart

3. On the Nextcloud server, update the below configuration in /etc/httpd/conf.d/nextcloud-ssl.conf

   RewriteEngine On
   RewriteCond %{HTTP:Authorization} ^(.*)
   RewriteRule .* - [e=HTTP_AUTHORIZATION:%1]

4. Login to Nextcloud server URL https://nextcloud.server.com and navigate to Settings → Administration → Security.
   1. In Brute-force IP whitelist section, specify the Zimbra server’s IP Range.
   2. In OAuth 2.0 clients section, specify the Name and Redirection URL of the Zimbra server. For e.g.:

      Specify Name – My Zimbra Server

      Specify Redirection URL – https://myzimbra.server.com/service/extension/oauth2/authenticate/nextcloud

   3. Copy the Client Identifier and Client Secret fields for the above entered Client. This will be used to update LDAP related configuration in the next step.

To enable Nextcloud for domain example.com, add LDAP entries for it by executing the following commands:

zmprov md example.com zimbraOAuthConsumerCredentials 
<Client Identifier>:<Client Secret>:nextcloud 
zmprov md example.com zimbraOAuthConsumerRedirectUri 
https://myzimbra.server.com/service/extension/oauth2/authenticate/nextcloud:nextcloud 
zmprov md example.com zimbraOAuthConsumerAPIScope 
'https://nextcloud.server.com/nextcloud/index.php:nextcloud_noop'