After upgrade to 5.3, nested virtualization on the windows 16 server does not work

I'm also having issues with nested virtualization. I am using Proxmox 5.3-5, and I'm currently getting the following error when trying to run Proxmox under a hypervisor:

TASK ERROR: KVM virtualisation configured, but not available. Either disable in VM configuration or enable in BIOS.

Any ideas? I like to run Proxmox in a test environment before making changes. I can do it on bare metal I suppose, but it's just a hassle. My CPU is an Intel Core i5 4570, which should be OK in theory.
 
How to fix?
did you try to set the machine type to an older version ? e.g. pc-i440fx-2.11

TASK ERROR: KVM virtualisation configured, but not available. Either disable in VM configuration or enable in BIOS.
then your hypervisor does not expose the kvm feature to proxmox
 
did you try to set the machine type to an older version ? e.g. pc-i440fx-2.11


then your hypervisor does not expose the kvm feature to proxmox

Sorry should have been more clear, I'm trying to run Proxmox within Proxmox. But you are right. I thought I had toggled the flag to enable nested virtualization, but when I went to check with the command "cat /sys/module/kvm_intel/parameters/nested" it returned N. I ran "echo "options kvm-intel nested=Y" > /etc/modprobe.d/kvm-intel.conf" and rebooted and everything started working. Thanks!