Referring to this thread which have similar situation:
I want to create a multisite, subdirectory, and want to use subdomains as options to create sub blogs.
For example, I added these subdomains in multi-domain settings:
Then, added A records,
Then when creating subblogs in multisite, they were under the above subdomains:
I got Internal Server Error in dir and dir1, in both in front-end and wp-admin
What do you think is the problem? Does the plugin function in this way? Is there anything wrong with the configuration?
Thanks in advance.