Hello,

i've no access to the backend but looking at the frontend i already found that the problems are due to misconfigurations.

Firstly i found this expression added to the field for responsive elements classname: .responsive-image img {width: 100% !important; }
As a result this breaks the javascript. The field is not done to include a CSS style but to include a CSS class name.
Remove it to fix the javascript error.

After that the problem with the landscape is due to the fact that the value for the mobile threshold and site width has been changed from 1024 to 400 pixel. Set the original value as in the image below.

If you are unsure about what you are going to change i suggest to retrieve a clean installation and eventually experiment on a staging area.

Best regards

John