When inserting the form script into a website it breaks my site

that is the script that generates plumsail

Dear @Guillermo_Martin_Gar,
There are multiple reasons why this might be the case. Our scripts are fairly straightforward, but if a site's engine tries to take control and transform our scripts, for example, to improve loading time, it might lead to issues. There might be other reasons for this too.

Can you give us a link to where the form is posted?