Lost access to my subdomain sites

Hi guys,

I SOOOO hope you can help me. I enabled Domain Mapping on my multisite that had some existing sites on it. Ever since doing so I can't access them. They either provide a 404 error or it just gives me the "Nginx is installed" page

I do hope this can be recitified as I made the cardinal sin of not making a backup before installing :slight_frown:

Support access is enabled