Adobe Sign will not send confirmation emails for new E-Signatures -- desktop + browser

Just as the title says, the attorney at our company uses Adobe Sign very regularly, and this functionality has ceased to exist for him. He owns a license for Adobe Acrobat Pro DC along with many others in our Enterprise plan, including myself, who do not experience this problem. I have re-authenticated his license to verify that all functionality should be available, and have also repaired Acrobat Pro DC and verified we are on the same version. 

This is not a spam/filter/quarantine issue, as the email confirmations do not send across multiple recipient domains, eg our own and Google. I have verified this functionality works on an Enterprise, and a non Enterprise Adobe Sign account with my own separate logins. I have verified that the E-signature requests are indeed sending from his Adobe Sign account, and are "in-progress" when checking the status online. In addition, the recipients successfully receive the E-signature requests in their Adobe Sign profile, but there is NO MENTION of the E-signature needing your attention via email. Most clients have no idea what Adobe Sign is, they just follow the link in the email from a known name, then type/write their signature, and proceed with their next email. I can't be troubled to ask them to go create an Adobe Sign profile, log into the website, check their inbox, and send it back... I've seen dozens of topics on this problem yet NONE OF THEM have valid solutions, or even suggested solutions. Please let us know what to do here