Flunlyismnestorianism .com

Elderly couple who I help with their had a dialog pop-up at start up.  Contained message that their computer was blocked and to call a phone number.  They didn't, they called me.  I advised them to cold shutdown and restart.  This was successful.  I have them running their AV - Windows Defender (they live on a fixed income).

My question: In the original dialog was the following URL: flunlyismnestorianism .com

Is this a virus?