Nova missing instance

Hi all,

A customer had contacted us stating their instance was not working and was unresponsive. They attempted to reboot it and it failed to reboot and went into an error status. I have had a look at the nova logs and nova seems to think the instance has "disappeared" and comes up with an error stating: "Instance cannot be found"

I have attached the full logs in the pastebin link. Has anyone come across this before?

https://pastebin.com/LWzvsc8u

Regards,