Admin Login will not display: 500 error

[ThinkEnvisage]

Moved site to new server. All is working, images, products add to cart, customer login is all working. When I go to admin I get "page not found".

I have confirmed that the config files are correct and the admin folder and files are there. What am I missing. I spent a good part of the day trying to troubleshoot this for the client and I am out of ideas.

Any help is greatly appreciated.

Thank you.