Realty Interface

My website builds single property websites for real estate agents. I need someone to go through it for bugs or how you would alter it to make it a solid application. This was hand coded by someone in Upwork and we started working on it in 2018 and things still are breaking. I want a review done with recommendations and responsiveness.

PHP | CakePHP | MySql | Magento | Linux Admin - Is the current developer's skill set on upward.

Example website: https://www.realtyinterface.com/property/?rpage=7118-glenbrook-road,-bethesda,-md&preview=1