Disable/Enable Azure monitor alert rules by azure automation powershell

Hi,

I have an azure monitoring alert rule where it will check the heartbeat of my virtual machine for every 5 minutes. But, the virtual machine itself will go offline everyday at 11 PM and will be started again on 9 AM on next day.

so I'm trying to use azure automation to disable/enable my alert rule at the same time. this is the code I've tried to use:

Write-Output "start job"
$vmResourceGroupName = <<resource_group>>
$vmName = <<vm_name>>

try
{
# Connection
Write-Output "connect to the VM"
$Conn = Get-AutomationConnection -Name AzureRunAsConnection
$rcConn = Connect-AzAccount -ServicePrincipal -TenantId $Conn.TenantID -ApplicationId $Conn.ApplicationID -CertificateThumbprint $Conn.CertificateThumbprint

# Stop the VM
Write-Output "Stop the VM"
stop-AzVM -ResourceGroupName $vmResourceGroupName -Name $vmName -Force
#first method that I use to disable my alert rules
Get-AzAlertRule -ResourceGroupName $vmResourceGroupName -TargetResourceId <<my_resource_id>> -DisableRule
#second method that I use to disable my alert rules
Disable-AzureRmActivityLogAlert -Name <<my_alert_name>> -ResourceGroupName <<my_resource_group>>
}
catch
{
if($_.Exception.Message)
{
Write-Error -Message "$($_.Exception.Message)" -ErrorAction Continue
}
else
{
Write-Error -Message "$($_.Exception)" -ErrorAction Continue
}
throw "$($_.Exception)"
}
finally
{
Write-Output "end job"
}

both of the method which I use returning an error that said my alert rules are not found.