Can't see Cartloom page in preview

I’ve set up my products on the Cartloom site. I saw them once on my RW preview, but now I can’t !!! Don’t know what I did to hide it. I see my header and below is just black.
Please can anyone help? I need to get this up today before Xmas.

PS. Is this the correct category for the question? I never know which to post in - stack, add-on or plugin?