Is this really the version you are looking for? Kentico 8 documentation is no longer updated. Use the switch in the header to choose your Kentico version.

Logon troubleshooting

If you cannot log in to the administration interface, please try the following:

If you are logging in to a new Kentico installation, the default user name is administrator, the default password is blank.

If your login credentials are incorrect, try resetting your account's password using the Forgotten password link.

Log-on page to Kentico administration interface

If none of these options helps, contact an administrator.