Same question here, but to reach everyone I better ask in english.
The app admin_notification was merged into the default notification app:
I want to create notification with CURL.
The OCC Command is working:
sudo -u www-data ./occ notification:generate \
admin "Short message up to 255 characters" \
-l "Optional: longer message with more details, up to 4000 characters"
But the webcommand not:
curl -H "OCS-APIREQUEST: true" -X POST \
https://<admin-user>:<admin-app-password-token>@<server-url>/ocs/v2.php/apps/admin_notifications/api/v1/notifications/<user-id> \
-d "shortMessage=<short-message>" \
-d "longMessage=<long-message>"
admin-user: User ID of a user with admin priviliges
admin-app-password-token: Password or an "app password" of the "admin-user"
server-url: URL with Webroot of your Nextcloud installation
user-id: User ID of the user to notify
short-message: Short message to be sent to the user (max. 255 characters)
long-message: Long mesage to be sent to the user (max. 4000 characters)
I´ll be pleasure about suggestions 
Cheers
