Problem:
When setting an e-mail recipient using the PDFMailRecipients registry setting, I get the following error message:

"Your message did not reach some or all of the intended recipients.

No transport provider was available for delivery to this recipient."

Solution:
If you prepend a "SMTP:" qualifier to the email address such as "SMTP:someone@microsoft.com", it should resolve the problem.

You can also use the "Win2PDF Mail Helper Application" to send email instead of the default MAPI client.  The "Win2PDF Mail Helper Application" is a free download available at:

https://helpdesk.win2pdf.com/index.php?/Knowledgebase/Article/View/189/15/win2pdf-mail-helper-download