I turned on debugging, here are the PHP errors when form submission doesn’t work:

[08-Jan-2016 16:52:49 UTC] PHP Parse error:  syntax error, unexpected 'LMS' (T_STRING) in /var/www/wordpress/wp-content/plugins/handl-utm-grabber/handl-utm-grabber.php(28) : runtime-created function on line 1
[08-Jan-2016 16:52:49 UTC] PHP Parse error:  syntax error, unexpected 'Ad' (T_STRING) in /var/www/wordpress/wp-content/plugins/handl-utm-grabber/handl-utm-grabber.php(28) : runtime-created function on line 1
[08-Jan-2016 16:52:49 UTC] PHP Parse error:  syntax error, unexpected 'LMS' (T_STRING) in /var/www/wordpress/wp-content/plugins/handl-utm-grabber/handl-utm-grabber.php(28) : runtime-created function on line 1

This is great, everything is working great now! Thanks so much!

For anyone interested is using this plugin with contact form 7, simply add the following code to your themes function.php file:

add_filter( 'wpcf7_form_elements', 'mycustom_wpcf7_form_elements' );

function mycustom_wpcf7_form_elements( $form ) {
        $form = do_shortcode( $form );

        return $form;
}

Then to your form add:

[utm_campaign_i]<input type="hidden" name="utm_campaign" value="%s" />[/utm_campaign_i]

[utm_source_i]<input type="hidden" name="utm_source" value="%s" />[/utm_source_i]

[utm_term_i]<input type="hidden" name="utm_term" value="%s" />[/utm_term_i]

[utm_content_i]<input type="hidden" name="utm_content" value="%s" />[/utm_content_i]

[gclid_i]<input type="hidden" name="gclid" value="%s" />[/gclid_i]

And to collect the data, on the mail tab add this to your email message:

Campaign Name:
[utm_campaign]

Campaign Source:
[utm_source]

Campaign Term:
[utm_term]

Campaign Content:
[utm_content]

Campaign GclickID:
[gclid]

Riskoff,

Did you add the necessary code to your theme’s function.php file?

add_filter( 'wpcf7_form_elements', 'mycustom_wpcf7_form_elements' );

function mycustom_wpcf7_form_elements( $form ) {
        $form = do_shortcode( $form );

        return $form;
}