Sorry, ich habe sollte auch mit zu erwähnen, die Probleme kommen mit dem Inhalt:

# --
# Copyright (C) 2019-2022 Rother OSS GmbH, https://otobo.io/
# added for OTOBO (http://otobo.de/)
# --

# This configuration is the standard way for running OTOBO under Apache 2.4 without SSL.
# Dynamic and static content is generated by the Plack app otobo.psgi.
# DEFLATE and support for HTTPS should be handled in separate configuration files.

# mod_perl is required

Error "mod_perl is required for Plack::Handler::Apache. Use apache2-httpd-cgi.include.conf as fallback."

Error "The Multi-Processing Module mpm_event is active but it isn' supported by OTOBO. Please switch to mpm_prefork."

Error "The Multi-Processing Module mpm_worker is active but it isn't supported by OTOBO. Please switch to mpm_prefork."

# Use a dedicated Perl interpreter for the current virtual host, usually the default virtual host
PerlOptions +Parent

# Preload otobo.psgi so that that the app doesn't have to be loaded again for every process.
# This also sets @INC.
PerlPostConfigRequire /opt/otobo/scripts/apache2-perl-preload_otobo_psgi.pl

# everything is handled by the PSGI app

# handle all requests, including the static content, with otobo.psgi
SetHandler perl-script
PerlResponseHandler Plack::Handler::Apache2
PerlSetVar psgi_app /opt/otobo/bin/psgi-bin/otobo.psgi

# Require is supported starting with Apache 2.4.
# No authentication and all requests are allowed.
Require all granted

# Limit the number of requests per child to avoid excessive memory usage.
# 1000 is the same value as the default value used by Gazelle.
MaxConnectionsPerChild 1000

in der Datei apache2-httpd.include.conf