Issue with Yahoo Business Mail

I created a Fill-in form in LiveCycle with button with "Submit" option as PDF the URL is set to mailto:customerservice@livewellmedical.com.  This works as desired for most customers, however, I have one customer that uses Yahoo Business Mail (online).  This customer does not get an email form to open when he clicks the submit button.  Any one have an idea on possible issues or fixes?

Any insight would be greatly appreciated.

Thanks

Brian