Authentication may be required for http://172.16.254.15/

Hi,

I'm receiving this message on some devices:
Authentication may be required for http://172.16.254.15

Each device is also showing the following message:
Unauthorized Manager Detected.
Manager IP : 172.16.10.158

(Spiceworks server IP is 172.16.10.158)

However I set a scan exclusion for each of these devices on the Settings / Network Scan.

I also tried submitting these devices credentials on Network Accounts for Scanning but still with no success.

What else could be causing this access to the devices?

Thank you!!!