nobody has created any of the schedules coz its occuring a the time of running backup manually or by scheduled backup jobs

it is in cluster also and it is giving failure audit of another node AP server failure log in DB server event viewer

we tried to take backup in both node [DB and AP servers ] at both it is rebooting and givng blue dump in windows. there also unable to find the errors

my exp is very less and so iam unable to find the root cause but iam trying my level best this is the site which made me to know more when ever a issue comes