The problem was created by some code in the htaccess from root.
So:
To present exactly my configuration:
I have
– http://maindomain.org with file directly in the root of my hosting. I know this may not be a best practice and i’ll change this.
Subdomain i was trying to set was in a folder which was along site my maindomain files.
- wp-admin/
- wp-includes/
- wp-content/
- s/
- .htaccess
On the main site i had install a securrity plugin from ithemes security which was somehow restricting me to install wordpress on a subdomain
The solution i chose was to backup and temporarily remove .htaccess from the root to install my wordpress.
Next step is to move my main site on a subfolder to prevent future problems like this.
I leave this here in hope others how get this error to find it. In case my response is messy don’t hessitate to suggest and edit or to contact me.
Thanks stackexchange