NC 17, No browser notifications

Hello everyone!

I have recently installed a NC instance and so far everything is working, apart from some trouble with browser notifications (there are none in the android app either, but that’s not as relevant for me).

The problem: Regardless of the browser used I do not get a notification for new messages, mentions or calls (or anything at all, really). When I close the conversation and someone messages me I do get the dot on the little bell on the top right, informing me that there is a message waiting, but there are no requests for browser notifications. I have opened a demo server at try.nextcloud.com, and there my browsers all ask to show notifications and then do so when allowed. Manually allowing notifications for my NC site does not change anything.

The Notifications app is installed. There are no errors in the nextcloud.log or the web server log files. The developer console (browser) just shows some info concerning deprecated libraries, but no failed connections or CSP errors. Where else should I look?

Some system info:
NC Server
NC Version: 17.0.2
OS: Debian 10.2
PHP: 7.3.11-1~deb10u1
nginx: 1.17.7-1~buster
DB: MariaDB 10.4.11+maria~buster

Gateway/Proxy
OS: pfSense 2.4.4-RELEASE-p3 (amd64)
Proxy: HAProxy 1.8.23 (18-1.8.23)

Thanks for reading! Please let me know if you require more information.