So I found the problem, i really dont know how but it work so here is the thing:
in the wordpress network set up menu says that you have to replace all the lines with that code.
The thing is that it tells you to write something that is wrong
the line in italic should be erased:
....
RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) YOUR-FOLDER/$2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ YOUR-FOLDER/$2 [L]
....
So it would be:
RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) /$2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ YOUR-FOLDER/$2 [L]