It seems that the device that you use to open the HA dashboard has an issue, not your HA, right?
Don’t you have another system to access your HA, or did you try another browser?
ps: you don’t have to mask your PRIVATE/LAN IP addresses; most of the users here have their network configured that way/with that IP range.
If your concerned about security, do not post you WAN IP.
Just to be clear, your server where HA is installed crashes or your PC (or laptop) with which you call the HA webpage (http://IP:8123) crashes? Or do you use the HA server as “desktop” as well, meaning you call the HA webpage on the same machine where HA server is installed?
Sorry, wasn’t clear for me. 
EDIT: @Nick4 was faster! 
Aren’t we a nice bunch! 
The problem is from the device that hosts HA. For example I tried to host it with the same settings but on my main PC and it works perfectly.
When I do it on my mini pc, the pc crashes completely and I have to restart the pc and eventually the HA server.
the server is the one who crashes. As I said just now in the other reply, the problem is from the server that hosts HA.
Do you need windows on that system?
Running HA virtualized on Windows is not the best route, maybe even the worst.
Did you install any additional integration already on HA or is it still basic?
FWIW, I ran my production and development copies of Home Assistant for over 2 years in exactly this way (Windows/Virtualbox) and never ran into problems or limitations that would justify calling it “the worst way”.
I guess you know very well that by using a desktop version of Windows, especially if you just use it to install a desktop virtualization software to run a server is not the best option. (and in my opinion one of the worst)
At first, you just waste resources and depending on your knowledge, your server might go down with every Windows update.
Of course, there are ways to prevent that, but still if someone thinks he/she has to hide a LAN IP would you still advise to go that route?!
On top of that: the issue that OP has, how would you advise to solve this, with Windows & VirtualBox in the game?
No, I agree on the IP masking discussion. I find many people on this forum take on complex setups they don’t seem to understand. Every person has to decide on their own if something is beyond their knowledge and experiences.
As to why this scenario crashes the PC, I couldn’t begin to speculate with the information provided. Makes me appreciate the job of a veterinarian.
If you don’t need Windows on that box, just install ProxMox.
+1 on what @francisp says but of course that’s because I know the capabilities of Proxmox since I use it for some years now and with 16Gb RAM (if that’s the config that you bought) what will you do with that much, only for HA.
With Proxmox you get an easy way to install extra services (virtual servers).
Now, with Windows, you waste already a few Gb’s on Windows itself and then on VirtualBox.
Also, performance wise, this is not ideal.
TBC: on my desktop & laptop, I use Windows myself, and this is for MANY years, so I have nothing against it!
Another option is to install HAOS directly (without any other software layer in between) on your system: Installing HAOS on a dedicated x86-64 PC - #11 by MichaelSidenius
I would prefer to keep Windows. I also need to run other programs besides Home Assistant.
if you want to keep Windows running, either try Virtualbox 6.1, or VMWare player.
Home Assistant crashes on my mini PC, but works perfectly on my main PC. Any ideas why? I’d prefer to fix it on the mini PC rather than installing Proxmox.
See my answer above:
I just installed virtualBox 6.1 and it’s working perfectly. Thanks
I have virtualBox 7.0 and it crashed too. Does it mean installing lower version the problem fix?
Can’t hurt to try (and yes, it should)
From Oracle VirtualBox website:
This was the exact cause of my issue too. 7.0.18 has been released on 03/05/24 and it seems to be working for me so far.