NextcloudPlus on a HP 260 G1 – Installation not working

after successful installation of Nextcloudplus to a raspberryPi and a longer operation period without problems I tried to install Nextcloudplus to a HP 260 G1 under a fresh installed Debian 9.4.
Apache2 was activated.
I tried several times to install nextcloudplus with the following command

curl -sSL | bash,

but always the installation-log ended with

“ERROR: Site nextcloud does not exist!”

I’ve copied the complete log of the installation. I cannot find the reason for the malfunction of the installation-process.
Has anybody of you got an idea why this doesn’t work?

Thanks to all,