External Forms Breaking

In the footer of my website is an external form embed from Dot Digital.

When I activate the ‘Protect external forms’ setting within the plugin, the forms break and no longer submit correctly.

The reason we activated this setting was the form was getting hit with a lot of spam but it seems to be causing more issues itself now having the setting on.

How can we fix this so I can have the spam protection on the form without breaking it?

Any help would be greatly appreciated as it is fairly urgent and causing issues across multiple sites right now.

Many thanks