Blocked web sites

So over the weekend, my daily Fortigate report started showing 24 attempts per day, to connect to a blocked web site from my boss's computer. Only problem is, he was not here or logged in remotely from home. The number of attempts also matches to an IP address that shows on the list of blocked sites attempted on the same report. But that IP address doesn't go to anything when I pull it up in my browser. We've ran a virus scan from two different programs. Both have come up clean. Is there anything I'm missing?