fastcgi-problem with dietpi x86 lighttpd nextcloud collabora [solved]

Troubleshooting
21 
uname -a
Linux DietPi 6.1.0-18-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.76-1 (2024-02-01) x86_64 GNU/Linux

cat /etc/issue
Debian GNU/Linux 12 \n \l

apt policy lighttpd
lighttpd:
  Installed: 1.4.69-1
  Candidate: 1.4.69-1
  Version table:
 *** 1.4.69-1 500
        500 https://deb.debian.org/debian bookworm/main amd64 Packages
        100 /var/lib/dpkg/status

I had same problem 2 weeks ago with my Z83_II (testing-“server”), but that is running “Trixie” and has 2 GB RAM, so i thought that could be a problem of to less memory (it was really swapping a lot while collaborate server was started in background).

Now i got the IGEL M350C with 4 GB and ran into the same problem (which was solved by this trick here) :wink:
I really just installed a pure debian without desktop, just ssh-server and systemtools from the choices i had while installing.

I started conversion with dietpi-script, rebootet and installed nextcloud+lighttpd, samba and pi-hole.