@kagbasi-ngc You can go to Settings > Logs to display the details of that resources error message. It should say something such as this:
vm.snapshot
{
"id": "7f3d5995-3ab8-bfd5-ec72-c36e98d8cc70"
}
{
"code": 24,
"data": [
{
"resourceSet": "UXh2bwwr9Lo",
"resourceType": "cpus",
"available": 0,
"requested": 4
}
],
"message": "not enough resources in resource set",
From my tests, you need to have free cpu, ram and storage of the same amount of the VM. So, to be able to snapshot that VM you would need 2 cpus and 16 GiB of ram in the resource.