After password reset redirected to wrong URL

Hello,

I have an issue: when users reset their passwords and click on “Reset password” button they are redirected to URL like this: 'https://FQDN:8080/owncloud/FQDN/owncloud/core/templates/403.php ( but password successfully reset)
The same situation i have with new user when he is trying to set password he is redirected to wrong URL.

Also if I use URL like this: 'https://FQDN/owncloud (without a slash at the end) I will be forwarded to the same URL ->https://FQDN:8080/owncloud/FQDN/owncloud/core/templates/403.php

If I use URL like this: 'https://FQDN/owncloud/ or 'https://FQDN/owncloud/login - everything is working and I see the main page of Owncloud.

Working URL:
https://FQDN/owncloud/login
https://FQDN/owncloud/
https://FQDN/
https://FQDN

I have:
owncloud version: 10.0.10.4 (on docker container)
Univention App 4.3 Appliance owncloud (ESX)
start site has been changed to -> apache2/startsite=owncloud/login
Server is domain joined.

Owncloud app settings are:
owncloud_domain: 'https://FQDN (where fqdn is my external domain name)
OWNCLOUD_SUB_URL: /owncloud

All other settings are default.

Could you please tell me how to change URL on “reset password” ir “Set password” button, and how to force “https://FQDN/owncloud” URL forward to “https://FQDN/owncloud/login

Thanks