This issue should be fixed in the nginx configuration. You can find it within the /etc/nginx/sites-enabled/
Usually, it will be a file with the same name as your domain name. Please open it and then find if you have something similar below.
location ~ \.php$ {
fastcgi_split_path_info ^(.+\.php)(/.+)$;
include fastcgi.conf;
fastcgi_param HTTP_PROXY “”;
fastcgi_buffers 8 16k;
fastcgi_buffer_size 32k;
fastcgi_read_timeout 300s;
client_body_buffer_size 128k;
fastcgi_pass unix:/run/php/php7.4-fpm.sock;
http2_push_preload on;
}
change location ~ \.php$ { to location ~ ^/(index|shopware-installer\.phar)\.php(/|$) { then restart your nginx