nginx error logging in

[fdmbs]

Hi to all,
i'm trying to make vbulletin 5.7.1 working with some problems...
i'm at the firse steps of loggin in.

i'm installing vbulletin on almalinux 8 with nginx 1.14

"core" folder is in /usr/share/nginx/html/vbulletin

i've installed without problems via web:

http://myserver/vbulletin/core/install/install.php

i've confirmed position of my core and frontend directory.
But when i finish and i click on "go to adminCP" the system send me to the page

http://myserver/vbulletin/admincp

i receive an error: nginx error! The page you are looking for is not found.

i think it's right cause it should be

http://myserver/vbulletin/core/admincp/

but even with this i get the error.

if i write manually

http://myserver/vbulletin/core/admincp/index.php

i arrive to the login page and if i enter my credential, i m redirect to

http://myserver/vbulletin/login.php?do=login

with the nginx errore like above...

in my nginx.conf i've added information found in installation package:

...\do_not_upload\nginx.vhost

nginx service starts without problems...

any suggestions?

thanks a lot

Davide