dashboard404 with add new site

Since you setup Multisite subdomain. The .htaccess file should be as follows.

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).*) $1 [L]
RewriteRule ^(.*\.php)$ $1 [L]
RewriteRule . index.php [L]

So please rename current .htaccess file to .htaccess.bak and create a new .htaccess file with the above contenets.

You can also refer the following WordPress documentation for more information about WordPress .htaccess files.

https://codex.www.ads-software.com/htaccess

i did that. still no dashboard in a newly added site

doesnt a new site need a database?
a single installation needs one, so seems logical a newly added site needs one too, wether being the existing one with a prefix, or a new one?

You can either create separate databases for each website or you can use single database for your blogs.

You an refer the following WordPress documentation to configure database as per your requirements.

https://codex.www.ads-software.com/Installing_Multiple_Blogs

thnx 4 ure reactions, but it seems hopeless. need multiple installs.
but then again, how do i make the sub-install end up as a subdomain??
there are no subfolders created with the newly added site through network admin, and it seems illogical to go trough all the multisite setup trouble, just to manually make a subfolder and new installation?
why is the newly added site 404? what does it lack? a db? fine. it has no folders, so how do i find THAT wp-config?? and how do i add a db to it, if it doesnt get installed as a normal installation? i can make db’s in my cpanel till the cows come home, it would matter if i cant define them to a ‘new’ install OR ‘added’ site.

This sounds like a configuration problem with your hosting provider. If you want to run WP multisite, all sites should go to the same document root. Some providers make each (sub) site have its own folder.

One way to check is to load a known file. For example, if your main site is site.com, try loading https://site.com/wp-login.php. That should work, now try it with your sub-site, https://site1.site.com/wp-login.php. If you are getting a 404, then your web server is not configured properly.

“then your web server is not configured properly. ” can you elaborate?

> “then your web server is not configured properly. ” can you elaborate?

Each web site has a document root. That is the folder that contains your files. For WP multisite, you want all your sites to use the same document root. Hosting providers will generally create each web site with their own document root by default. You do not want that. You need to figure out how to configure them to use the same one.

For example, when you create your domain.com, its docroot will be something like:
/path/mydocroot
when you create two more sites site1.domain.com and site2.domain.com, you will get two new doroots:
/path/site1docroot
/path/site2docroot

That is one cause of 404s with WP. The other is .htaccess file is not configured properly.