Emails are different depending on what email address I send too

Testing out the echosign PDF, from Salesforce, by sending the request to different email addresses.  When I send the signature request to a Gmail account, the correct email with subject, Signature requested ***************, and link is received.  When sending to my corporate account ,Outlook365, I receive a different email with subject "

Please delegate*********to an authorized signer" and no link to document.

Why would this happen? And how do I fix the issue?