Problem with CCR1036-12G-4S v6.4

Hello

I have a problem with mikrotik router ccr1036-12G-4S v6.4

I had configured OSPF and IP Tunnels whith IP sec, whith wich i have communication whith all our braches.But
every 5 or 8 days router stops and it is freezed. In this case i have to do physycaly restart, because i can not connect
to router.After this restart it return in normal mode.


What i have to do to avoid this problem?

Thank you