Sorry - added that last bit prior to seeing your comment - It is not my theme, I am just a user of the product like you.
I am sorry you can’t get it to work. I haven’t had that problem. In fact I have had nothing but good experiences with Live Composer (which is not actually a part of the theme as such, but rather a plugin that you can add to any theme).
Not sure if you have tried different browsers, or talked to your hosting company to see if maybe you need any updates otherwise.
Had you tried to add new content areas and modules? Just putting that out there. What you are going through is unusual, but could be the result of backend settings, hosting issues, or any number of different things.
Maybe try activating a different theme.
I can tell you from having used almost everything out there with regards to page builders that Live Composer has been my best experience.
Beaver Builder is close, but it comes with a big price tag if you want the pro version. You may be able to get by with the free version, however.
Thrive would be next in line for me, but also has some limits I didn’t care for - frontend content editing was not one of them but also costs a fair amount for unlimited use.
A lot of people like Visual Composer but I wound up fighting with that to get it to show exactly what I built in it originally, both in backend and frontend modes. It is a little cheaper and comes with many additional 3rd party modules. I am happy to be free of it, however.
I like the new DIVI Builder better than VC personally - it is faster and easier to keep track of in the back end. No front end option though. not sure if you can buy it individually - I got it by buying into the Elegant Themes Lifetime membership, in addition to a pile of themes and other cool plugins.
Having no issues myself with Live Composer personally, I can tell you with a fair amount of confidence that something is up with your situation one way or another. It is not the theme or Live Composer.
Hope you can figure it out.