New Forms Mail To formula URL not working

Hi, I have a mailto formula set up so that when we click the button, it opens a new email in Outlook with the emails address To and the Subject prepopulated. This works absolutely fine on the old forms, but on the New Forms it's opening a new browser window instead of Outlook. Is there any way to get it to open a new email from Outlook from the New Forms?

The formula is:

"mailto:"&[Compliance work - Email to Use]
&"?subject="&[Subject of Email]

In my Windows settings the default application for MAILTO is Outlook.

So far it's taken me to yahoo, gmail and hotmail home pages, each time I refresh the page it takes me to a different mail provider. It seems to be ignoring the Mailto function. As said, on the old forms it works perfectly fine.

------------------------------
Personal Tax Team
------------------------------