action="mailto:*email address*" in form not working over HTTPS

I want to create a simple contact page for my website. I created a form like this (using React).

<Form   action="mailto:btrorapps@gmail.com"   method="post"   encType="text/plain"   autocomplete="off">

It's got some Form controls to gather data and a submit button.

Works perfectly fine when I run it on localhost. When I update the code for my website that uses HTTPS I get this weird autofill error.

If I ignore all that and type a message anyway and submit, I get this.

How can I fix both of these problems?