These are the shortcodes I used to create a custom form which contains the same field like the standard form.
[newsletter_profile]
[newsletter_profile_field name="email"/]
[newsletter_profile_field name="first_name"/]
[/newsletter_profile]
This is the form generated by the shortcodes.
<form action="#" method="post">
<input type="hidden" name="nk" value="0-0">
<div class="tnp-field tnp-field-email">
<label>E-Mail</label>
<input class="tnp-email" type="text" name="ne" required="" value="[email protected]">
</div>
<div class="tnp-field tnp-field-firstname">
<label>Vorname</label>
<input class="tnp-firstname" type="text" name="nn" value="John">
</div>
<div class="tnp-field tnp-field-button">
<input class="tnp-submit" type="submit" value="Profil speichern">
</div>
</form>
This is the shortcode for the standard form with just email and firstname configured.
[newsletter_profile /]
This is the standard form generated by the shortcode.
<form action="https://localhost/www.mydomain.de/?na=ps" method="post">
<input type="hidden" name="nk" value="0-0">
<div class="tnp-field tnp-field-email">
<label>E-Mail</label>
<input class="tnp-email" type="text" name="ne" required="" value="[email protected]">
</div>
<div class="tnp-field tnp-field-firstname">
<label>Vorname</label>
<input class="tnp-firstname" type="text" name="nn" value="John">
</div>
<div class="tnp-field tnp-field-button">
<input class="tnp-submit" type="submit" value="Profil speichern">
</div>
</form>
Both forms look pretty much the same except the form action in row 1. The standard form has the correct URL while the custom form has just the hashtag symbol (#) as the form action.
Clicking on the profile save button results in case of the standard form in saving the field values while in case of the custom form the values are just cleared from the field and are not saved.