Embedded drop shipping site not working

Hi guys, firstly I’m not great with code or anything but I need to get this working.
Trying to use the iframe tool to embed a custom clothing site from my drop shipping service. It is an http site which obviously doesn’t work so when i added it i changed it to a https site, it appears fine and the link to get to the actual site works but when you click on links to the clothing it doesn’t work. can someone tell me what could be wrong?
Webpage below:
www.kiaifit.com/merchandise

really? no one?