What does Error #268D3 mean?

Hello. I have recently ran into a suspicious message that appeared via my web browser. It says ** YOUR COMPUTER HAS BEEN BLOCKED ** Error #268D3 Please call us immediately at: (855) 712-8551

Please tell me, is this a scam? Because it looks like one! Besides, I do not know how to remove Error #268D3 virus. And why is this annoying message appearing on my computer screen?