The form works when previewed but has disappeared online.

I copied the script into my html5 file. The form appears when I preview the file offline, but when I uploaded my files to the server, there is no form.

I've tried:

-building a new form and using the new code

- moving the code to a different div

- deleting the css file and the form still doesn't show up in the plain html

Please help! Why isn't the form working on my server?