Dont receive push with ntfy

[Offerel]

I have setup NextCloud and Dav Push app. Have setup DavX5 on the phone. When i use FCM, i see a event created in the webinterface of NextCloud instantly. When i use ntfy (hosted on the same machine, but different subdomain), i only see, that the channels/topics are created in the ntfy app on the phone, but a event created in the webinterface will not be pushed to my phone. I dont see any error message in the nextcloud logfiles.

Im relative sure, that this is because of using my own ntfy instance, but i have no idea, where to look for any issues. Other topics are working fine.

[Offerel]

I have found, that using enable-reservations and message-size-limit was the issue. If I remove both from my server.yml make it work. I have to look more in this.