Can't get Zoneminder to stream

I have Zoneminder set up and configures in my HA. The configuration is minimal:

zoneminder:
  - host: ZM_HOST
camera:
  - platform: zoneminder

ZM_HOST is the IP of the Zoneminder install and it is running over http with no authentication.
I have some Unifi camera’s in stand-allone mode and my Doorbirs doorbells connected to this.

The result is that I can see the camera’s in the front-end, but I get some weird things:

  1. When I am remote, the full-screen streams don’t open. I click the camera preview, but the stream never loads in full screen.
  2. I can’t cast the camera’s to my Chromecasts. I see two different things:
    2.1 With the doorbirds, the cast is initiated on the Chromecast, but I never get to see an image (only a placeholder icon) (EDIT: I am wrong, I see this when trying to access the Doorbirds directly)
    2.2 When I try the same with the Unifi camera’s, I get a message that the source does not support cast.
    What am I missing? Can anyone give me some hinds? I’ll gladly provide more info on my configuration but don’t know what you might need, so just ask.

Thanks,

Thomas