Only letters and minus sign (-) are allowed

[pinatz]

Hello Guys.

I have to integrate Activecampaign contact form in a Page on my website with Prestashop 1.7

When I add these raws

<div class="_form_12"></div><script src="https://kmsoltec.activehosted.com/f/embed.php?id=12" type="text/javascript" charset="utf-8"></script>

i get error when I save.

The error says: "Only letters and minus sign (-) are allowed"

Same strings in Prestashop 1.6 works.
Do you know why?

Thanks to everybody
Matteo