drop to grub rescue mode after upgraded to proxmox 8 for a few days

[xpking]

Dear all,

Some days ago I upgraded from v7 to v8.
Now suddenly I got grub rescue mode only.

I searched through google but cannot understand what I can do in grub rescue.
Secure boot in Bios is disabled.

Please help! Thank you.

Welcome to GRUB!
error: prohibited by secure boot policy
grub rescue>

 

[xpking]

Anyone can help please?