Lighttpd

Hello ,
I use Ubuntu 18.04 and Lighttpd 1.4.45.
I want to make diagnostic data collected by a background process and processed in a shared mem accessible to our service staff via cgi programs written in FPC. The data should be available on different HTML pages via a browser. The Html pages are created by cgi programs and updated by JS. JS calls another CGI-program, which reads and provides the necessary data from the shared mem. The JS calls the cgi-program without problems, but the cgi-program cannot connect to the shared mem. Call the cgi-program from the console and everything will work. The connection to the shared mem is established and the data can be read and written. If the cgi-program is called by the lighty - no reaction.
cgi, fastcgi and fastcgi-php are enabled. The basic configuration looks like this:

server.modules = (
"mod_indexfile",
"mod_access",
"mod_alias",
"mod_compress",
"mod_redirect",
)

server.document-root = "/var/www/html"
server.upload-dirs = ( "/var/cache/lighttpd/uploads" )
server.errorlog = "/var/log/lighttpd/error.log"
server.pid-file = "/var/run/lighttpd.pid"
server.username = "www-data"
server.groupname = "www-data"
server.port = 80

server.http-parseopts = (
"header-strict" => "enable",# default
"host-strict" => "enable",# default
"host-normalize" => "enable",# default
"url-normalize-unreserved"=> "enable",# recommended highly
"url-normalize-required" => "enable",# recommended
"url-ctrls-reject" => "enable",# recommended
"url-path-2f-decode" => "enable",# recommended highly (unless breaks app)
#"url-path-2f-reject" => "enable",
"url-path-dotseg-remove" => "enable",# recommended highly (unless breaks app)
#"url-path-dotseg-reject" => "enable",
#"url-query-20-plus" => "enable",# consistency in query string
)

index-file.names = ( "index.php", "index.html", "index.lighttpd.html" )
url.access-deny = ( "~", ".inc" )
static-file.exclude-extensions = ( ".php", ".pl", ".fcgi" )

compress.cache-dir = "/var/cache/lighttpd/compress/"
compress.filetype = ( "application/javascript", "text/css", "text/html", "text/plain" )

include_shell "/usr/share/lighttpd/create-mime.assign.pl"
include_shell "/usr/share/lighttpd/include-conf-enabled.pl"

server.modules += (
"mod_dirlisting",
"mod_staticfile",
)

Does anyone have any idea why I can't read from the shared mem with the cgi program?

Thanks in advance.