Click Send for Shared Commenting and follow the steps in wizard to add a note and recipients, and so on. When complete, the message appears that the email is created in the email program, but the email is never created. Usually it would appear in the Outbox, and could be sent. Nothing ever appears.

As a workaround, I tried to "send file, attach to email' to send the review enabled pdf. The email opens with the pdf attached, and i sent. First time i got an error that the file could not be found, and the email was not sent. Second attempt, it appeared to work, no error, but the email was not sent.
Acrobat Pro DC continuous release version 2018.011.20038
Windows 7
Outlook 2010 version 14.0.7197.5000 (64bit)