custom permalinks won't work properly

Hi everyone,

I read the permalinks guide on wp and tried to set up my custom permalinks, but with no luck.

I put wp on my own space in https://www.mydomain.com/site and set up wp to load the content on https://www.mydomain.com, as described here:
https://codex.www.ads-software.com/Giving_WordPress_Its_Own_Directory
(i am saying this just in case it can be connected to the problem described below)

now i am using a custom theme which works with custom post type called ‘portfolio’.

i tried to get permalinks like this:
https://www.mydomain.com/post-name/

but selecting writing /%post-name%/ but i got:
https://www.mydomain.com/site/portfolio/post-name/

is there a way to get the following permalinks structure?
https://www.mydomain.com/post-name/
or, in alternative:
https://www.mydomain.com/portfolio/post-name/

thanks in advise!