Business Central - Demo Install, cannot login to web client - Add nav user

The user account you are currently using cannot login to Business Central.
Add another user account with super permission.
Error: You are not setup as a valid user

https://docs.microsoft.com/en-us/previous-versions/dynamicsnav-2013r2/jj672890(v=nav.71)

If you are restoring from an external database, Add your windows account to the database using SSMS to ensure the powershell can even interact with the db.
Give it db_owner to the db and master

From powershell or administration shell, run as administrator
New-NAVServerUser MicrosoftDynamicsNavServer -WindowsAccount Cronus\Chris

New-NAVServerUserPermissionSet DynamicsNAV71 –WindowsAccount cronus\chris -PermissionSetId BASIC

New-NAVServerUserPermissionSet CRONUS –WindowsAccount cronus\Joe -PermissionSetId SUPER


eg.
New-NAVServerUser BC150 -WindowsAccount mypc\test New-NAVServerUserPermissionSet BC150 –WindowsAccount mypc\test -PermissionSetId SUPER