Curl installer: "Distro not supported" Buster

ello,

i have an LXC-Container with Debian GNU/Linux 10 \n \l. with Proxmox.

The curl installer says:

root@nextcloudpi:~# curl -sSL https://raw.githubusercontent.com/nextcloud/nextcloudpi/master/install.sh | bash
Getting build code...
Hit:1 http://ftp.debian.org/debian buster InRelease
Hit:2 http://ftp.debian.org/debian buster-updates InRelease
Hit:3 http://security.debian.org buster/updates InRelease
Reading package lists... Done
Reading package lists... Done
Building dependency tree       
Reading state information... Done
ca-certificates is already the newest version (20190110).
sudo is already the newest version (1.8.27-1).
wget is already the newest version (1.20.1-1.1).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
/tmp/nextcloudpi.TxgNip ~
/root

Installing NextCloudPi...
etc/library.sh: line 277: lsb_release: command not found
ERROR: distro not supported:
Debian GNU/Linux 10 \n \l

What is wrong?