Permalinks issue with deployment – 404 Error

Hi there,

I am having issues with deploying my clients website with their permalinks: cart.com.hk

I have tried setting the permalinks back to default (http://www.cart.com.hk/?p=123), which then work, and then back to custom (/%year%/%monthnum%/%day%/%postname%/) but it again goes back to showing a 404 error page.

A couple sample links that I wanted to work:
http://www.cart.com.hk/about/
http://www.cart.com.hk/products/seasonal/silly-witches/

Product Permalink base when set to default also works: http://www.cart.com.hk/?product=sample-product
but I wanted it to be /products/%product_cat%/

Any advice would be greatly appreciated, thank you!

The site is WordPress 4.3.2