NCP 1.51.0: HPB down - push server can't connect to the Nextcloud server

Hi,
after I had to shutdown my Raspi for some electric installation, after reboot the HPB is down.
I have experienced such things in the past and they magically did resolve themselves after some hard or soft reboots. Not so now.

There are some messages about “unexpected end of file”:
> push server can’t connect to the Nextcloud server
> error sending request for url (https://localhost/index.php/apps/notify_push/test/cookie): connection error: unexpected end of file

|NextcloudPi version|v1.51.0|
|---|---|
|NextcloudPi image|NextCloudPi_RaspberryPi_v1.50.3.img|
|OS|Debian GNU/Linux 11. 5.15.84-v8+ (aarch64)|
|automount|yes|
|USB devices|sda|
|datadir|/media/myCloudDrive/ncdata/data|
|data in SD|no|
|data filesystem|btrfs|
|data disk usage|41G/116G|
|rootfs usage|5.2G/29G|
|swapfile|/var/swap|
|dbdir|/var/lib/mysql|
|Nextcloud check|ok|
|Nextcloud version|25.0.3.2|
sudo ncc notify_push:self-test

? redis is configured
? push server is receiving redis messages
? push server can load mount info from database
?? push server can't connect to the Nextcloud server
  error sending request for url (https://localhost/index.php/apps/notify_push/test/cookie): connection error: unexpected end of file
sudo ncc notify_push:setup

This setup wizard is intended for use on single server instances
where the nextcloud server, web server/reverse proxy and push daemon all run on the same machine.
If your setup is more complex or involves any kind of load balancing
you should follow the manual setup instruction on the README instead
https://github.com/nextcloud/notify_push
Press enter to continue or ESC to cancel...

Push binary seems to be running already
?? failed to run self-test.
test output: ? redis is configured
       ?? using unencrypted http for push server is strongly discouraged
       ?? push server url is set to localhost, the push server will not be reachable from othe r machines
       ? push server is receiving redis messages
       ? push server can load mount info from database
       ?? push server can't connect to the Nextcloud server
	 error sending request for url (https://localhost/index.php/apps/notify_push/test/cookie): connection error: unexpected end of file

See the steps in the README for manual setup instructions: https://github.com/nextcloud/notify_push

Any ideas?

I looked into the other threads about “HPB down” but that did not bring a solution.

I don’t know how you system was running before but likely there is some issue with a config. it’s unlikely you have valid certificate for localhost so https://localhost/.. must be wrong address - it should be either http://localhost or https://cloud.mydomain.tld/..

Did you check this thread already?

Setting up Files (High Performance Backend)

Most things seem fine. But I am stumbling when I am asked to run
occ app:enable notify_push

Because then I get
-bash: occ: command not found

Edit: I found the solution to this. I have to run:
sudo -u www-data php /var/www/nextcloud/occ app:enable notify_push

Fun note:
Yesterday evening I did update the undelying OS and afterwards started the Raspi again. Now NC / HPB was up again for some hours.
There is no logic behind this as I did try reboots before in all ways.

Not-fun note:
This morning HPB was down again even though there was no restart or any other event that I am aware of.