WordPress Multisite with subdomains

Point each Multisite subdomain at the network's document root in cPanel or DirectAdmin, so the sites resolve instead of 404ing.

A WordPress Multisite network using subdomains needs each subdomain created in the control panel and pointed at the network's document root, not at a directory of its own. Applies to shared and reseller hosting on cPanel and DirectAdmin.

Multisite serves every site from one WordPress installation and decides which site to show from the hostname in the request. If a subdomain has its own document root, the request never reaches WordPress and you get an empty directory or a 404.

cPanel

Go to Domains → Create a new domain.

Enter the subdomain and set the document root to the same directory as the Multisite installation.

Creating a subdomain in cPanel with a shared document root

That is normally public_html. If the network runs on an addon domain, use that domain's directory instead.

cPanel proposes a new subdirectory as the document root by default, such as public_html/shop. Accepting it is what breaks Multisite. Overwrite it with the network's own document root.

Correcting an existing subdomain

If the subdomain already exists with the wrong root, select Manage beside it on the Domains screen.

The Manage option beside an existing subdomain

Set the new document root and select Update.

Setting a new document root

DirectAdmin

Go to Subdomain Management → Add Subdomain at user level.

DirectAdmin always creates its own document root, at /domains/yourdomain/public_html/subdomain, so this must be corrected after creation rather than during it.

Select the pencil icon beside Docroot for the new subdomain.
Set public_html and private_html to custom, both pointing at the Multisite installation's document root.
Save.

Setting a custom document root in DirectAdmin

Allow a few minutes for DirectAdmin to rebuild its configuration before testing.

Consider a wildcard instead

Adding a subdomain by hand for every site does not scale, and it is easy to forget when a network lets users create their own sites.

A wildcard subdomain — *.yourdomain.com pointed at the network's document root — covers every site, present and future, with one entry. Set it up the same way, using * as the subdomain name. You will also need a wildcard DNS record and, for HTTPS, a wildcard certificate.

Verify

The subdomain loads its Multisite site rather than a directory listing or 404.
It appears correctly under My Sites → Network Admin → Sites.
HTTPS works. A standard certificate does not cover subdomains; check the padlock on a subdomain, not just the main domain.

Fix "Unable to create directory"