Dear Syahir,
I deleted the form from my home page and saved the page, then simply pasted it back and resaved the page, and tadaammm… Slider is now working. So I don’t know how but it is now solved itself. 🙂
(By the way, the Customer Service of my e-mail marketing provider told me that if WP loads jQuery automatically then the subscription form should work without loading its own jQuery from their CDN sever so I can delete the line.)
Anyway, thank you… Graphene and its support is THE BEST! 🙂
Adrian