Different languages of the primary site

OK, let’s see … so you already created a new site in the network admin. What is not working? Do you have access to the dashboard of this new website?

Yes, I have created a new site (apart from the main that is in EN) and I would like to have the same things in it, but in GR.

I do not see something that is not working now, however I do not know what to do next.

I have access to the dashboard of the Network Admin and to the main site’s dashboard (in EN), but NOT in the dashboard of the created site (let’s assume in GR).

Sorry for being late with this answer. There was a lot to do for the WordCamp Turin. ??

Do set up a multisite with subdomains? The .htaccess-file has the content that the setup proposed?

Sorry for being late, too! I believed I had answered.

Do I have to copy the original .htaccess-file somewhere? In a diferrent folder?

If you have a subdomain setup then you should have a .htaccess like this:

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# uploaded files
RewriteRule ^files/(.+) wp-includes/ms-files.php?file=$1 [L]

# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^(wp-(content|admin|includes).*) $1 [L]
RewriteRule ^(.*\.php)$ $1 [L]
RewriteRule . index.php [L]

My .htaccess file is the following:

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ – [L]

# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ – [L]
RewriteRule ^(wp-(content|admin|includes).*) wordpress/$1 [L]
RewriteRule ^(.*\.php)$ wordpress/$1 [L]
RewriteRule . index.php [L]

Is there a problem, since I do not have the second quote/paragraph?

No, no problem … how is the name of the gr site?

https://boutsivaris.gr/ is the original (working fine) site and the GR site should be https://gr.boutsivaris.gr/

These domains have different IP addresses:

boutsivaris.gr 193.92.97.18
gr.boutsivaris.gr 54.72.52.58

Could you check this first?

With an IP-checker, for the first I see the same IP as you show me. For the GR, I get this:
Error determining IP Addresses for gr.boutsivaris.gr

Did I do something wrong with the site’s URL?

You should check this where you bought your domain. Very often there you have access to a panel for DNS configuration. Maybe you can ask also somebody from your hosting support. gr.boutsivaris.gr could be a CNAME for boutsivaris.gr (like https://www.boutsivaris.gr).

I have fixed the IP addresses and now they match! ??

From the File manager, I have copied all the files etc from the main site to the subdomain’s gr.boutsivaris.gr directory.

However, still the site is not available.

Oh, there are no files to copy … these 2 domains should point to the same installation. This is one of the advantages of the multisite.