UTM froze and not able to reboot Ubuntu 20.04

Good afternoon,
I encountered a strange issue: during normal operation with the virtual machine it frozen.
After I close the window and re-open it Ubuntu doesn't boot again and remains on EFI:

I lost already 2 times (today and yesterday) all my work since I am not able to access anymore to my VM.
I tried to reboot from kernel 5.4.0-110 and 109 without any success.
I tried to run again an old version with 5.4.0-105 today, I worked on it until few hours ago and again it frozen and display the same EFI screen (so I lost again all my work).
Even trying to reboot from kernel 5.4.0-104 doesn't work (no I did not get any update on linux).
I tried also with different versions of UTM: latest (3.2.3), 3.1.15 and also 2.4.1. Same result.
Thanks

**Configuration**
* UTM Version: 3.2.3, 3.1.15 and 2.4.1
* OS Version: 12.3.1
* Apple Silicon M1 PRO chip