Domain Mapping Issue

I'm trying to use the Domain Mapping plugin for the first time and I'm having a problem. I have tried to map the domain to the site Defeat DIPG Store. But instead of directing me to this site, I am redirected to the main site (

I'm sure I'm just doing something wrong, but I've tried changing all of the options that seem relevant, and I haven't fixed the problem. Can you figure this out? I've granted support access to my site.