Trying to open the Company Portal as a user after Intune Enrollment shows the below 

When clicking continue to Enroll you then get the error

The device is already registered in Intune

You will need to re-enroll the device using the following method

Delete ( or as much as you can ) :  HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Enrollments

Re-enroll PC as the correct User using the Access Work and School Method

If it asks you for the Server URL for MDM you can use this 

EnterpriseEnrollment-s.manage.microsoft.com