blank white pages in subdomains- workaround, no fix required?

Assuming you have a main domain created Main.  com

all you have to to do from your main admin is, Add a domain instead.
for example Domains>Add Domain
make sure the appropriate user is selected, Simply create your sub as a domain.
Example:
SUB.Main. com

NOTE: Once the sub.domain is created from main admin it will appear under domains in the user account.