I would suggest that the asset is likely included in some other scanning target configuration. It could be an IP Range, some kind of Active Directory scanning, or something else. If it is a Windows asset you can check the Scan time tab to give you an idea of how it is being scanned.
To get rid of it you will need to figure out the scanning target that is causing the failed scan, then either:
- Re-configure that scanning target to avoid that particular asset (e.g. don't include that IP address or OU in the target configuration)
- Assign an appropriate credential to the scanning target (as previously suggested) so the error won't occur
- Add an scanning exclusion for that asset. The device will still be scanned, but the scan will be dropped and won't generate an error.
