HTML formatting in emails is not working

HTML formatting in emails is not working

When I use the "send mail" function on Deluge Script, it no longer respect the HTML tags for bold, italic, underline, etc.. When I am in the Script Builder, the preview seems right, but when I test the forms and the mails are sent automatically, the text is all written as if it were plain text aligned to the left. Also, it doesn't show some characters (such as à, ó, ñ) and sometimes it doesn't even respect line breaks. I didn't have any of these problems before, and I didn't change anything in the script. I don't know what could be the problem.