Gateway Error 502 Can't Access Site

Hi

I was logged into the admin area of my site and went to change the settings on my Slider. Did nothing else and was not in the CSS code, just in the slider settings. A 502 Gateway Error appeared and I could not access the site from any portal!

I went into my browser history and clicked on a link to the Admin from earlier today, got in, checked everything and saved it as it was at that point, with the original slider settings.

The site came up and looked great.

Now I can’t access the site or the admin. Anyone have any thoughts as to what would make it disappear, reappear and disappear if I didn’t touch the code? Is there a way into the Admin around this?

Help!

Cheers,
Margot