Help!! Domain pointing

Hello, my wordpress is at https://www.inlanddrift.com/idrift
I was using Pyrmont v2

except it wont access it. heres what happend….

It was ready to go public and i wanted to point it to the original domain, https://www.inlanddrift.com but for some reason it wouldnt do it. So, I went into the settings section in the wordpress back end….and i changed the part where it said “blog address” which was oringinally https://www.inlanddrift.com/idrift. I changed it to say https://www.inlanddrift.com

now i get Internal Server Error – Read

The server encountered an internal error or misconfiguration and was unable to complete your request.
Reference #3.b0a32ed0.1253926500.9ac2c

and when i try to log into the administrative end of it, i get the same error, so now I don’t know how to get into the administrative end to fix the domain.