I investigated an issue recently where a customer could not enrol a specific user into Intune using Android Enterprise Fully Managed.
Issue
During enrolment via Android Enterprise Fully Managed, when the user attempted to sign into the Intune app, they received the following message.
Page not found - we couldn't find what you were looking for
Fix
The root cause was their account had been added into Intune as a Device Enrolment Manager . DEM Accounts are not supported for Android Enterprise Fully Managed enrolment or Corporate-owned devices with a work profile. Removing the DEM account resolved the issue.