Qlik Cloud Site can't be reached

[DataWhisperer]

Good Day,

I have Qlik Cloud/Business running and I am displaying an app with just two sheets on a screen in my office - this app has an extension that automatically cycles through my sheets every minute. 

Qlik works perfectly on my laptop and was perfect on my screen for the last 3 days, now I am just getting the following, "This site can't be reached. ". Full details below. 

P.s. the screen is running off a small separate PC set-up plugged into the screen.