Datepicker on Mobile

Hi, does anyone know why the datechooser doesn’t work on mobile? I selected “date” as the field, but the calendar itself doesn’t appear on mobile, but works on tablet and desktop.

You can refer to the second contact form on this page as reference. https://fiona.timinyli.com/contact/

Any help would be greatly appreciated. Thanks in advance!

https://www.ads-software.com/plugins/si-contact-form/