I have installed the Multi-Domains plugin with no problem. I can create sites using the original domain e.g. domain1.com. However, when I tested creating websites using my second domain e.g. domain2.com, it did not worked. After I hit "Add Site" button, it redirects me instead to that second domain http://domain2.com/wp-admin/network/, which is page not found.
By the way, I have already configured the wildcard sub-domain of my second domain to point it to the IP of my WordPress installation.
What could be the problem?