If you want users to log into the Lansweeper web console, you'd have to either create an AD account for them or a local Windows account on your Lansweeper web server.
You can only assign a user role to a user that has an associated Windows account, as the user will need to log into the web console with this account to be able to use the features included in his role. Users you add with the Add User button under Configuration\User Access & Roles don't have an associated Windows account. More information about user roles can be found here: https://www.lansweeper.com/kb/102/restricting-access-to-the-web-console.html
If you want to assign user roles you will need to add a Windows account (local or domain) under Configuration\User Access & Roles instead.
- If your Lansweeper server is in a domain, there will be an Add AD User button to add domain users. Keep in mind that the resulting popup will only list domain users that have already been scanned. Instructions for scanning additional users can be found here: https://www.lansweeper.com/kb/172/how-to-scan-users.html
- If your Lansweeper server is in a workgroup, there will be an Add Local User button to add local users configured on the server hosting your Lansweeper web console.