I had everything working with a mastersite (www.aamembers.org.nz) and two subsites using subdomains. Then I deleted the subdomain so as to set up the Add On domain name to be one of the subsites.

Once creating the add on domain (aaconvention.org.nz - convention.aamembers.org.nz) I checked the settings for urls for this subsite:

aamembers.org.nz/multisites/convention
www.aamembers.org.nz/multisites/convention
convention.aamembers.org.nz
aaconvention.org.nz
www.aaconvention.org.nz

However now the default page for aaconvention.org.nz is going to the default hosting page rather than aaconvention.org.nz/home or aaconvention.org.nz/index.php

Do you know why this would be?

I copied over the .htaccess as part of subdomain process and had tested the whole thing with another random domain name earlier which worked but I am not sure what has changed apart from using a different addon domain name.

Regards, Amie

If the same procedure work for another domain, check that this domain that is not working has the same DNS server - perhaps you have this domain defined on another name server and therefore still defined with other values.