First thing would be to see if there are any external or physical impacts,
as VD mentioned fan / temperature issues (also high ambient temperature),
but it can also be loose / defective cables, bad power source, network issues, external control systems ...
It can be worth to see if the endpoint still reboots if you disconnected the network.
Next steps can be to do a factory default reset (recommended to do a xconfig / xstatus and a backup upfront).
As you are running on TC5 I would also strongly recommend to do a firmware upgrade.
But if the system crashes all the time it could also affect an upgrade, so I would recommend to
check first if you have a valid service contract so you can contact tac if needed.
Contacting TAC would be also what I would do if all of the above did not help.
