Plugin Activation Error on New Website Install

I have been trying to install the WPMU DEV Dashboard Plugin on a website but after activating the plugin and entering the login credentials to WPMU I am directed to a white screen with an error message. Tried the install on a different site and get the same message.

{“code”:”rest_no_route”,”message”:”No route was found matching the URL and request method”,”data”:{“status”:404}}

Any thoughts on how to resolve the error?