Has anyone else experienced a total inability to run "web.skydemon.aero" on any browser on a Mac?

I notice no one replied. I have to run Safari for Skydemon web. Only thing I use it for as Safari is rubbish, too much spinning wheels. 
It works on safari but it won't print anything. Pulls up the print option so you can tick what boxes you like but after you 'ok' it nothing happens, not even a screen view of it.

All,
In view of the many comments re SD on the MAC, and the fact that I had no problems previously with Yosemite & whilst using Safari, (printing and everything), can anyone give guidance on removing El Capitano and reinstalling Yosemite?

Many thanks.