Form does not send on iPhone (works in all other browsers)

Hi everyone,

I don’t know when this bug was introduced to my code, but for some reason my Contact Form 7 form no longer submits on iPhones. It works on iPads, all android devices, IE, Firefox, and Chrome. But there is something different about the iPhone’s Safari browser that is not triggering the post action of the generated input button.

Here is my form code:

<div id="entry-form" class="entry-form">
<p><h2>Your Information:</h2></p>
<p class="label"><label for="input_name">Name (required)</label><br />
    [text* your-name id:input_name]</p>

<p class="label"><label for="input_email">Email (required)</label><br />
    [email* your-email id:input_email] </p>

<p><h2>Your Message:</h2></p>
<p class="label"><label for="input_subject">Subject</label><br />
    [text your-subject id:input_subject] </p>

<p class="label"><label for="input_message">Your Message</label><br />
    [textarea your-message id:input_message] </p>

<p><h2>Captcha:</h2></p>
<p class="label"><label for="input_captcha">And finally...prove you aren't a robot!  Type the characters you see in the picture below.</label>
<div style="text-align:center;">
[captchac contact-captcha]
</div>
[captchar contact-captcha id:input_captcha]
<div style="text-align:center; font-style: italic;">Enter the characters as they are shown in the image above.</div></p>

<div style="text-align:center;">
<p>[submit id:submitButton class:button class:white "Send Message"]</p>
</div>
</div>

And the form itself can be found at:
https://www.davidquiring.com/contact

I have monitored the HTTP incoming/outgoing requests/responses with my laptop by switching Safari’s user agent to pretend to be an iPhone, and no post action is being generated at all when the send button is clicked.

I have tried to debug this for hours now, and would really appreciate any insight you might be able to lend.

https://www.ads-software.com/plugins/contact-form-7/