Is WordPress to WordPress SSO possible ?

Hi developers and users this my first post here. I am running a WordPress site on a free hosting . I didn’t enable Multisite feature during installation by using the script installer of the hosting provider. But I enabled it by editing wp-config.php . But when I create a new subdomain using my main wordpress site’s dashboard the subdomain won’t be created ! It maybe the issue with the hosting provider. So I was thinking that if I make separate installation by creating a new subdomain using cpanel and then is there any way to link both the wp installations in the main domain and in subdomain ???