I subscribed long ago to max threw the app on my phone. I just got roku and it won't let me log into it on roku.
Have you downloaded the app onto the Roku?
If it is already installed on Roku, uninstall it, reboot the Roku and try reinstalling the app.
Be sure you try to log in with the username (probably email) and password known to the MAX account, not with your Roku credentials.
This is a Roku issue that needs to be fixed. I can log in to MAX on all my other devices except the Roku. Wants me to connect to my provider but when I do it tells me my email is already in use. Something is broken on the Roku MAX app.