When creating a new push notification and and generate the required event it should trigger the push notification but does not generate errors nor notification
The cmn_notif_device table is set up properly for the corresponding user as stated on KB0855301
Although the notification works when we change it to email type and the cmn_notif_device and the user is subscribed to the notification, The sys_push_notif_app_install for the user is inactive or has another app in the application record.
Validate the sys_push_notif_app_install table for the users you expect receive the notification, the active field has to be enabled. Additionally, if there is no record of a user you can create it.
Always make sure that the push message added refers to right application (for example "ServiceNow Classic Mobile Application") in the sys_push_notif_app_install table for affected user