500 internal server error

I have a domain I bought through GoDaddy, with hosting by Godaddy. I have my main site in the root folder of my FTP server. I also have 2 more domains in the /_sites/ folder. I had one domain in there that works fine, but I recently bought another domain and it is not working. Through Godaddy, I point the domain to /_sites/DOMAIN2/, a folder I have created for the new domain, but it gives me a 500 internal server error. The domain in the /_sites/DOMAIN1/ folder works fine.

I set it up a year ago and I forget what I did to make it work. Anyone have any idea? I’ve tried putting wordpress in there and it still doesn’t do anything.