Not in sudoers file

Hi, I am new at NextCloud. Currently I am using the latest Raspberry PI image.
Setup went fine, got certificates, etc.

However, I am now getting an internal server error and just want to reboot the RaspberryPi3. But I cannot get past the sudo part. I log in as the NCP user (I have no other users) and do sudo, but it tells me that the user is not in the sudoers file and that the incident will be reported…

Everything I try to do to get NCP in the sudoers file requires me to be root (sudo) first. So I am in a loop here: to grant a user sudo permissions I first need that user to have sudo permissions.

Any help would be appreciated!

EDIT: after editing the password for the PI user via the webinterface I can now login as that user and even do sudo. Weird: I thought the PI user was replaced by the NCP user? How come it is still there?

it is not replaced, we just add a ncp user for authenticating to ncp-web.

in any case, note that you can reboot from the web interface (power button icon)