Login page redirecting to itself

Hi

I’ve just had a new multisite set up on my existing wordpress install. I have no problems logging in to the dashboard on my 2 pre-existing sites. (m.microscooters.(com.au/.co.nz)
However, when I’m in the dashboard and try to access my new site https://www.mxscooters.co.nz from the dropdown it just takes me back to the login screen. I enter my details and it then redirects me to the blank login page. No error messages to indicate why this is happening. The URL for the login screen shows as: https://www.mxscooters.co.nz/wp-login.php?redirect_to=http%3A%2F%2Fwww.mxscooters.co.nz%2Fwp-admin%2F&reauth=1

The site itself seems to be working, just showing the default wordpress theme and content as I haven’t been able to edit anything yet.

Does anyone have any solutions for this?

Thanks

Matt