Ajax Login Broken

Hi, I am working on a site https://theguardiansofearth.com and every time I log in using the login with ajax link and then attempt to access the backend of the website, I am directed to wp-login and have to log in again. I have a login page and register page that I am quite happy with and work great, is there any way to change the login and register links to load these specific pages in the same modal form or even just as a regular page, thanks a lot. Kind regards, Pete.

P.S. It seems like the search box is missing on your forum so I apologies if this is a duplicate issue.