Slider not working in Firefox

Agreed. Thanks for sticking with the conversation, I appreciate it.

I have checked again on another computer and found that
it does not work until the cookies are accepted and the page reloaded
I have tested this scenario 3 times, each time the same result, it works after the cookies acceptance

not sure why your cookie validator blocks the slider ...

Hi Ced. I wanted to post this in case it helps anyone else. It turns out the issue was caused by the Kickstart Cassiopeia module when the cookie notice is enabled. I raised this with Maarten Blokdijk, the developer who is very helpful. He has updated the module so that the page reloads after the user accepts the cookie notice. 

ok great, thank your your useful feedback and solution