Vm with home assistant - avery few weeks it stops working

hallo, i have vm with home assistant, and all working great, just avery few weeks it stops working , for example today i am not able to open the UI .
“ip_address:8123” page dont open , of course dont word also nabu casa , but the terminal command line is working, is there any command i can use to check what is not working ? i would like not to restart the VM , cause everytime i do it virtualbox have some trouble …
so anyone can tell me which command to use in the terminal to check what is wrong ?
i tried “core restart” but after 15 minutes is still “processing” …

after 20 minutes the core restarted and all is working normal again , is there a way to understand what happened ?