Every time I try to preview the form, the page fails to load.

I have tried previewing the form on both Internet Explorer and Chrome. As soon as the page begins to load it fails and asks if should kill the reloading progress.

I have opened your form and was able to see what you mean. I have cloned your form and I was able to reproduce the issue you're having. Aside from the form being long, it also has many conditions and large images. I also noticed that there are a lot of Conditions that already has "missing fields". Could you please delete those conditions that have "missing fields" already as it also adds up to load processes.

Also, I have disabled the "AutoFill (Continue Forms Later)" function of the clone version of your form and it somehow loads faster than before. Even though you haven't filled the form yet, it will start scanning the form for changes. That is why we normally advise our users to use the "session" workaround. The information on how you can do that is found in this guide: How-to-Save-Forms-and-Continue-Later

Thank you.

You may also want to consider dividing your form into pages using "Page Breaks". 

Here's the clone version of your form where I used "Page Breaks" to divide it into sections.

https://form.jotform.com/62326825918968

I hope this helps. Thank you.