I was in the same situation.
Issuing the commands
sudo systemctl enable php-fpm
sudo systemctl start php-fpm
moved me one step further.
I don’t have errors on /var/log/nginx/error.log
Page on browser presents the following message:
Whoops, the web server could not write required files to the filesystem.
Running the following commands will fix the issue most of the time:
Cannot write to log file: “/opt/librenms/logs/librenms.log”
Make sure it exists and is writable, or change your LOG_DIR setting.
If using SELinux you may also need:
semanage fcontext -a -t httpd_sys_rw_content_t ‘/opt/librenms/logs/librenms.log(/.*)?’
restorecon -RFv /opt/librenms/logs/librenms.log
Check your log for more details. ( /opt/librenms/logs/librenms.log )
If that doesn’t fix the issue. You can find how to get help at https://docs.librenms.org/Support.