Recently I spent hours banging my head against my desk while trying to change the wordpress network domain name of a site I was workng on. What I observed was that I could change the domain of a site as a wordpress network super admin, but upon doing so I could no longer log in to the individual site’s dashboard. After much trial and error I stumbled upon a solution that actually works quite well.

Surprisingly, the solution is not to change the domain name at all. Instead, simply enable the “WordPress MU Domain Mapping” plugin and map the desired domain name to the existing site.

How to Change the WordPress Network Domain Name For a Site:

1. As a wordpress “network administrator”, make sure that the “WordPress MU Domain Mapping” plugin is installed and activated.
2. If you’ve already tried changing the domain and site name of any individual sites, first change them back and ensure that you’re restored full functionality.
3. Log in to the dashboard of the individual site you wish to change the domain of.
4. Select Tools > Domain Mapping
5. Input the domain you wish to use for this site, and select “Primary domain for this blog”.
6. Verify that your web server and DNS are configured to reflect the new domain.

And that’s it! Your site should now be responding on the new domain name.

WordPress multisite network documentation: http://codex.wordpress.org/Create_A_Network