Sometimes when creating a network in multisite and picking subfolders, you may find the subfolder blogs have no theme applied (seemingly) or they are unstyled, and you cannot login to the sub sites admin area
What went wrong?
Well, on the WordPress side.. nothing. This is all server side unfortunately. I’ve seen this happen mostly on hosting account where the WordPress install was in a folder, as an add-on domain, or basically anywhere other than the root of the account and on the main domain.
The subfolder blogs all work on the basis of htaccess rules. While the setup procedure requires you to add new rules to the folder’s htaccess file (or the file itself if there is none) it actually the server side that needs to be told to actually read that file. Simply being present does not ensure the file is read.\
So yes, Apache can – and does by default in some cases – ignore htaccess files in subfolders, usually following the one in the folder above it.
If you are on a shared host and do not have access to Apache config files via the terminal or ssh or WHM, then you will need to contact your webhost support team and let them know your new htaccess file is not being read properly and they will have to force it.
If you have a VPS or dedicated, or are even working locally and can access Apache confgif files, you need to find the httpd.conf file under /etc/ or the vhost files, and add this line:
AllowOverride FileInfo Options
This should allow the extra htaccess file in that folder to be read properly.