Notification device problemIssue There is a user who is not receiving notification mails. When a notification is triggered and in the notification preview, and a mail should be sent to hime a message similar to the following error is found in the email log: Notification 'Request Item Assigned to Group' (556a52ecdb4348108cdc9cf3db9619dd) excluded recipients because user has no usable devices: 'XXXXXXXXXXX' (b0ab49ebdb6bff00aa429475db961944) According to the ServiceNow Knowledge article KB0758267, the resolution to this is to ensure that the user has an active and valid notification device. In this scenario, the user has a valid notification device Even though it was correct , after deleting the notification device and re-creating it, the same problem still persists. CauseIt happens when a user is subscribed to the notification without having a channel (cmn_notif_device).So for this issue to occur, the sequence of steps could have been1. User subscribed to the notification (creates sys_notif_subcription record)2. User created a notification channel using Notification Preferences. (creates cmn_notif_device record)ResolutionDelete the subscriptions for the affected user in sys_notif_subscription table and subscribe to the notifications again (if you want the user to receive emails for these notifications) For more information, visit our documentation page Subscription Based Notifications