Installation of ntfy integration does not work

I run homeassistant under proxmox. In the documentaion to 2025.5 I found the integration ntfy (ntfy.sh) for simple notifications. I use my own DNS server (pihole) with my local domain “.local”.

I installed ntfy as a service in proxmox with a self signed certificate. Startup went okay. I can run “ntfy publish homeassistant test” and “curl -d ‘test’ ntfy.local/homeassistant” commands in proxmox and get the push notification on the ntfy smartphone app.

In the homeassistent terminal “curl -d ‘test’ ntfy.local/homeassistant” also works without problems, so homeassistant has no problems reaching the server and DNS resolution works.

Now I wanted to install the ntfy integration.
I started wit + Add integration and found ntfy to install. I got a menu “ntfy” and " Set up ntfy push notification service" requesting me to enter the service URL, which was preconfigured with “https://ntfy.sh” (the public server).

Instead of “https://ntfy.sh” I entered my own server https “ntfy.local” and clicked “verify SSL certificate” off. I also tried pure http with http “ntfy.local”.
In both cases the installation failed with “Failed to connect”.

When I tried in my desperation with http “10.0.0.170” I got success. ntfy is installed with “10.0.0.170” and “No devices or entities”. It also worked with https “10.0.0.170”, verify SSL certificate set off.

Why does it not accept ntfy.local ?

Can I use it without problems with http and IP address instead of DNS name ?

in the configuraion.yaml I use my own address or do I have to use the IP address ?

# ntfy notifications
notify:
 - name: "ntfy hackerd"
   platform: ntfy
   url: "https://ntfy.local" # this or "https://10.0.0.170" ? ? 
#  token: not needed
   topic: "homeassistant"  

Are you using a custom integration or the official core integration?

Just had this same issue. Ended up being that I was running v1 of the ntfy container. Bumped it to v2.12.0 and HA was able to connect