My contacts birthdays 'calendar' does not show up in Nextcloud

Hi there!
I saw a post on which everyone agreed on the fact that the Contacts birthdays calendar is created/updated every time we edit or create a contact with a birthday date. But this is not the case for me.
After importing my contacts from a file, nothing happened. I created a new contact with a birthday date a couple of hours ago but there is still no contacts birthdays ‘calendar’, see below:
image

Please, can someone help me to troubleshoot this issue?
Many thanks!

From digging through Nextcloud posts (https://help.nextcloud.com/t/how-can-i-create-the-birthdays-calendar-again/7020/13, https://help.nextcloud.com/t/birthdays-have-disappeared-from-the-nextcloud-calendar/29779) it seems like this can only be done via console command.
Please create a gitlab-issue, so that this problem can be tracked by the devs.