"Reply Email" Inbound Action not sending email to external email addressesIssue You have an inbound action with Action Type = Reply Email so that the instance will send a reply email depending on the conditions of the inbound action. When a non-user sends an email to the instance, the reply email is not sent. The following will be logged in the email log: "Reply Email not sent for '<inbound action name>', empty user_id".CauseThis is expected behaviour due to how email processing in the instance works. The instance classifies any email address not in the sys_user table as sent by the Guest user.ResolutionThere are two workarounds available to send reply emails to non-user. 1) Setting up autoreply for emails sent to Service-Now mailbox. 2) You may use the "Automatically create users for incoming emails from trusted domains" option in https://<instance>.service-now.com/email_properties.do? which would create a user for each sender.